This document provides supporting information for the User Agent Accessibility Guidelines (UAAG) 2.0 for designing user
agents that lower barriers to Web accessibility for people with
disabilities. User agents include browsers and other types of software that
retrieve and render Web content. A user agent that
conforms to these guidelines will promote
accessibility through its own user interface and through other internal
facilities, including its ability to communicate with other technologies
(especially assistive
technologies). Furthermore, all users, not just users with disabilities,
should find conforming user agents to be more usable. In addition to helping developers of browsers and media players, this
document will also benefit developers of assistive technologies because it
explains what types of information and control an assistive technology may
expect from a conforming user agent.
This document provides explanation of the intent of UAAG 2.0 success criteria, examples of implementation of the guidelines, best practice recommendations and additional resources for the guideline.
The "User Agent Accessibility Guidelines 2.0" (UAAG 2.0) is part
of a series of accessibility guidelines published by the W3C Web Accessibility
Initiative (WAI).
May be
Superseded
This section describes the status of this document at the time of its
publication. Other documents may supersede this document. A list of current
W3C publications and
the latest revision of this technical report can be found in the W3C technical reports
index at http://www.w3.org/TR/.
Editor's Draft of UAAG 2.0
This document is the internal working draft used by the UAWG and is updated continuously and without notice. This document has no formal standing within W3C. Please consult the group's home page and the W3C technical reports index for information about the latest publications by this group.
Web Accessibility Initiative
This document has been produced as part of the W3C Web Accessibility Initiative (WAI). The
goals of the User Agent Working Group (UAWG) are discussed in the Working Group charter. The
UAWG is part of the WAI Technical
Activity.
No
Endorsement
Publication as a Working Draft does not imply endorsement by the W3C Membership. This is a
draft document and may be updated, replaced or obsoleted by other documents
at any time. It is inappropriate to cite this document as other than work in
progress.
Patents
This document was produced by a group operating under the 5 February 2004 W3C Patent Policy. The group does not expect this document to become a W3C Recommendation. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.
A user agent is any software that retrieves, renders and facilitates end-user interaction with Web content.
Users interacting with a web browser may do so using one or more input methods including keyboard, mouse, speech, touch, and gesture. It's critical that each user be free to use whatever input method or combination of methods works best for a given situation. Therefore every potential user task must be accessible via modality independent controls that any input technology can access.
For instance, if a user can't use or doesn't have access to a mouse, but can use and access a keyboard, the keyboard can call a modality independent control to activate an OnMouseOver event.
What qualifies as a User Agent?
The following tests can be used to determine if software qualifies as a user agent for the purposes of these guidelines. It divides potential user agents into Primary Agents (the traditional "browser"), Extensions and Plug-ins, and Web-based User Agents.
If the following three conditions are met then it is a Primary User
Agent and Must Conform to UAAG:
- If it is a standalone application; and
- If it interprets any w3c specified language; and
- If it provides a user interface or interprets either a procedural
or declarative language that may be used to provide a user interface.
If the following two conditions are met then it is a User Agent
Extension or Plug-In and Must Conform to UAAG:
- If it is launched by, or extends the functionality of, a Primary
User Agent; and
- If post-launch user interaction either becomes part of, or is
within the bounds of, the Primary User Agent.
If the following three conditions are met then it is a Web-Based User
Agent and Must Conform to UAAG:
- If the user interface is generated by the interpretation of either
a procedural or declarative language; and
- If this interpretation is by a Primary User Agent, User Agent
Extension or Plug-In; and
- If user interaction is not passed to and from the Primary User
Agent, User Agent Extension or Plug-In, or if user interaction does
not modify the Document Object Model of its containing document.
Relationship to the Authoring Tool Accessibility Guidelines (ATAG) 2.0
While it is convenient to think of user agents retrieving and rendering web content for one group of people (end-users) that was previously authored by another group (authors), user agents are frequently involved with the process of authoring content.
For these cases, it is important for user agent developers to consider the application of another W3C-WAI Recommendation, the Authoring Tool Accessibility Guidelines (ATAG). ATAG (currently 2.0 is in draft) provides guidance to the developers of tools regarding the accessibility of authoring interfaces to authors (ATAG 2.0 Part A) and ways in which all authors can be supported in producing accessible web content (ATAG 2.0 Part B).
The Role of User Agents in Web Authoring
The following is a list of several ways in which user agents are commonly involved in web content authoring and the relationship between UAAG 2.0 and ATAG 2.0.
- Preview tool: As authors edit web content, they often preview their work in user agents to test how the content will be appear and operate.
- ATAG 2.0 includes a special exception when "Previews" are implemented with pre-existing user agents, so there are no additional requirements on user agent developers in this case.
- Checking tool: Authors often make use of user agent error panels (e.g. HTML validity, JavaScript errors, etc.) during authoring.
- ATAG 2.0 Part A would apply, but likely would not include any additional accessibility requirements beyond what is in UAAG 2.0.
- If a user agent includes an "accessibility checker", then the developer should consult checker implementation guidance in ATAG 2.0 Part B.
- Edit modes: Some user agents include a mode in which the user can edit and save changes to the web content, modifying the experience of other users.
- In this mode, the user agent is acting as an authoring tool and all of ATAG 2.0 would apply.
- Automatic content changes: Some user agents (and/or user agent plug-ins) may automatically make changes to the retrieved web content before it is rendered.
- This functionality is not considered an authoring tool because the changes are made to the user's own experience, not the experience of other users.
- Providing a platform for web-based authoring tools: Many web applications serve as authoring tools and they make use of user agent features in order to deliver their functionality (e.g., undo text entry, adjust font size of the authoring tool user interface etc.)
- User agent developers should consult ATAG 2.0 to understand the ways in which web-based authoring tools can depend on user agent features.
UAAG 2.0 Guidelines
The success criteria and applicability notes in this section are normative. Guideline summaries are informative.
PRINCIPLE 1 - Ensure that the user interface
and rendered content are perceivable
Implementing
Guideline 1.1 - Provide access to alternative content.
Summary: The user can easily determine which pieces of content have alternatives such as alt text or longdesc (1.1.1) and interact with the text to see the available
alternatives (1.1.3). The user can also choose at least one alternative such as alt text to be always displayed (1.1.2), but it's recommended that users also be
able to specify a cascade (1.1.4), such as alt text if it's there, otherwise longdesc, otherwise filename, etc.
1.1.1 Configurable Alternative Content Defaults:
The user can specify which types of alternative content to render by default. (Level A)
- Intent of Success Criterion 1.1.1:
When the author provides alternative content, it is wasted if the user agent doesn't render it for users who need it. Default alternative content is a global option because it is an unreasonable burden for users to change the rendering options every time they visit a new page.
- Examples of Success Criterion 1.1.1:
- Sally is blind. In the browser's preferences dialog box, Sally specifies that she wants alt text displayed in place of images, and that the document should reflow to allow the entire alt text to be displayed rather than truncated.
- In the browser's preferences dialog box, Ben chooses to always display the alternative ("fallback") content for embedded objects, such as videos.
- Brin is deaf. She toggles a menu item which turns on the display of all captions for video and audio content.
- Related Resources for Success Criterion 1.1.1:
1.1.2 Browse and Render:
When a rendered element has alternative content, the user can render alternatives according to the following: (Level A)
- synchronized alternatives for time-based media (e.g. captions, audio descriptions, sign language) can be rendered at the same time as their associated audio tracks and visual tracks, and
- non-synchronized alternatives (e.g. short text alternatives, long descriptions) can be rendered as replacements for the original rendered content.
Note: User agents are encouraged to also provide the ability to display alternate content with, rather than replacing, the primary content (e.g. as a pop-up, tooltip, or annotation).
- Intent of Success Criterion 1.1.2:
a. There are times when users cannot gain meaningful information from images, charts, graphs, etc. (non-time-based media elements).The author may have provided synchronized alternatives for the media. Users should be able to easily discover the synchronized alternatives provided, and have them render synchronously with the default media.
b. There are times when a user cannot gain meaningful information from a non-time-based media element (images, charts, graphs, etc.). The author may have provided alternatives for this. The user should be able to easily discover the alternatives provided, and have them render in place of the default media.
- Examples of Success Criterion 1.1.2:
- Sam is deaf. He is watching a video on a web page. He cannot hear the audio. The author has provided captions for the video. The user agent detecting that captions exist, makes the caption button visible. The caption button toggles the captions on/off.
- Sue is blind. She is watching a video on a web page. She cannot see the action on the screen. The author has provided audio-descriptions for the video. The user agent detecting that audio-descriptions exist, makes the AD button visible. The button toggles the audio-descriptions on/off.
- Mary has a learning disability. She is reading a page with many images. The images are distracting. Mary is able to turn the images off, and reveal the alternative text (@alt) that the author provided. The alternative text is rendered in place of the images. Mary has the option of having the size of the image remain same or fit the size of the text.
- Mary also cannot make sense of the graphs. The author has provided long descriptions for the graphs. Mary toggles the long-description feature. The browser detects the presence of valid @long-descriptions and renders an actionable icon inline after an image. Mary can click on the icon, opening the long-description for that particular graph.
- Related Resources for Success Criterion 1.1.2:
- See Success Criterion 4.1.2: Name, Role, State, Value,
Description
1.1.3 Identify Presence of Unrendered Alternative Content:
The user can specify that content be rendered with an adjacent indicator when unrendered alternative content is present (e.g. an icon to indicate an image has a short text alternative). (Level A)
- Intent of Success Criterion 1.1.3:
When the author provides alternative content, it is wasted if users cannot find it. The user agent should make the presence of alternative content evident to the user. Users should not have to hunt and examine every time to see if it includes such content, because such searching can be time-consuming, especially for users whose disability makes input difficult, tiring, or painful. The user should be able to easily identify which items have alternative content, rather than being merely informed that alternative content is somewhere in the view.
- Examples of Success Criterion 1.1.3:
- Tinan has repetitive strain injuries and seeks to limit scrolling. The user agent renders distinct visual icons in proximity of content that has short text alternatives, long descriptions, and captions. If the icon forces the text to extend beyond a fixed size container the user agent uses global preference settings to determine whether to expand the container, provide scroll bars, or truncate the content.
- Aosa is blind. When rendering a Web page using synthesized speech, the user agent generates an audible tone to signify the word being read is an acronym, and Aosa can press the * key to hear the expansion. When the phrase being read is the Alt text for an image, another tone indicates that Aosa can press + to hear the longdesc.
- A button is displayed beneath the playing video to indicate that captions are available and to let the user toggle their display.
- Related Resources for Success Criterion 1.1.3:
- (Refer to the SC about handling layout/reflow options.)
1.1.4 Rendering Alternative Cascade Order:
The user can specify the cascade order in which to render alternative content. (Level AA)
- Intent of Success Criterion 1.1.4:
For a given piece of non-text content the author may have provided one or several alternatives. For example, an image may have different versions based on resolution, ‘alt text’ (@alt) or a link to a long description (@longdesc). A video may have bandwidth alternatives, caption files in different languages, and audio descriptions in different languages. Users can choose which item(s) to render by default, and specify the order of the cascade of alternatives to be rendered if the author did not provide a type of alternative.
- Examples of Success Criterion 1.1.4:
- Mary has a learning disability. She finds looking at images on a webpage very distracting. Mary would like to see all images rendered in the following order. First, for images with long descriptions have the long description rendered in place of the image. If the long description does not exist, she wants the ‘alt text’ to be rendered. If neither is available, Mary wants the file name rendered. Added functionality would allow Mary to right click (context menu) on an image to list and select the rendering of the available alternatives (thumbnail, original size, full screen, low resolution, high resolution, alt text, long description, file name)
- Juan is hard of hearing. He wants to always see video on the page. Also, Juan would like the Spanish language track used if available, along with Spanish captions as a default. If these are not available, he wants to see the video with English audio and captions. If no captions are available Juan wants the video and English audio. Added functionality would allow Juan to right click (context menu) on an video to list and select the rendering of the available alternatives (still image, caption languages, audio languages, audio-description languages)
- Related Resources for Success Criterion 1.1.4:
- Web Content Accessibility Guidelines (WCAG) 2.0; Guideline 1.1 Text Alternatives and Guideline 1.2 Time-based Media (http://www.w3.org/TR/WCAG20/)
Implementing
Guideline 1.2 - Repair missing content.
Summary: The user can request useful alternative content when the author fails to provide it. For example, showing a filename in place of missing (1.2.1) or empty (1.2.2) alt text. The user can ask the browser to predict alternative content if it is missing (1.2.3) or notify the user if the content cannot be rendered (1.2.4).
1.2.1 Repair Missing
Alternatives:
The user can specify whether or not the user agent should generate and render repair text (e.g. file name) when it recognizes that the author has not provided alternative content. (Level A)
- Intent of Success Criterion 1.2.1:
When alternative content is missing, it is sometimes useful for users
to have access to alternative information, such as the
filename. Users need to control the flow of this
information, because an uncontrolled flow can be distracting and time-consuming. This is particularly important for users with some disabilities, who may not be able to use some forms of content (e.g. images) or may even need to avoid some forms of content (e.g. animations) and therefore choose to replace them with alternative content.
Users need to control the flow of the content when this information is added, because in some cases cases truncating the content to fit its container will make the document unusable (e.g. if important information becomes hidden), while in other cases expanding the container will make the document unusable (e.g. when important cues no longer line up correctly).
Because the definition for repair text is only for alternative content required by the specification it would not require generating transcripts of audio using speech recognition, for example.
- Examples of Success Criterion 1.2.1:
- Ray is blind and counts on alternative text descriptions for images. There is an image in web content that does not have alternative
text provided. The browser displays the string '(image canoe.png)', which includes the file name because that is the
only available information about the image.
- Bintu is deaf and relies on captions to replace audio. A video does not have captions. Bintu selects a caption
button, and is informed that no captions exist. The player
then analyzes the video soundtrack and provides speech to text
translation served as captions. Note: this is an advanced example, not a requirement.
- Related Resources for Success Criterion 1.2.1:
1.2.2 Repair Empty
Alternatives:
The user can specify whether or not the user agent should generate and render repair text (e.g. file name) when it recognizes that the author has provided empty alternative content. (Level AAA)
- Intent of Success Criterion 1.2.2:
When an author has chosen to code web content for alternative text but
not provide any text information (e.g. an empty alt) the user may still
need to know any information available about that web content. Some authoring tools may insert empty alternative text by default, even though this is is contrary to accessibility guidelines, and this can prevent users from getting useful information about the element.
- Examples of Success Criterion 1.2.2:
- A user wanting additional information on an image can right click on an image to get a context menu, then choose properties to get available information about the image without have to find the image in the source code.
- A photo-sharing web site automatically generates web content
with text alternatives. When the photos are initially uploaded, or if
the person posting the photos chooses not to caption a photo, an
empty text alternative is automatically generated. A person with visual
impairments uploads a batch of photos and needs to know which photo is
which in order to provide the photo description. The user agent provides
a menu option that displays all known information about that file
including filename and selected camera info (date, time, size, type, etc.).
- Related Resources for Success Criterion 1.2.2:
1.2.3 Repair Missing Associations:
The user can specify whether or not the user agent should attempt to predict associations from author-specified presentation attributes (i.e. position and appearance). (Level AAA)
- Intent of Success Criterion 1.2.3:
Users can use the appearance or position of an item to determine its importance when scanning a document for information. Assistive Technologies mostly rely on structured text, such as text coded as heading or labels. If the browser uses heuristics to identify text that stands out from others, it can render the page with the best guess of what the structure could be.
- Examples of Success Criterion 1.2.3
- Saidah uses a web-based text to speech app to read web pages when away from her home computer. She tries to find a news article on a multi-car accident on the freeway she overheard people talking about on the way to library. She goes to a news website to look for an article on the event. The website has no headings on the list of current events articles but has a long list. Saidah does not want to listen to the teaser for each story, and selects a command in her browser to figure out the headings from the appearance of the page. The browser notes the consistent use of a CSS style for phrases in each paragraph that are bold, in a different color and a larger font size. The browser then redraws the page with those phrases marked as headings. Saidah then uses the feature in her text-to-speech app to read out the headings and quickly finds the article on the car accident.
- Mateus is using a screenreader to complete a form. The form fields are not labeled so he does not know what should be entered in each field. He selects an option in his browser to render the page with structured text, which guesses that the text to the left of each form field is the label, and re-renders the page with the text structured as a label. Mateus finishes completing the form.
- Related Resources for Success Criterion 1.2.3:
1.2.4 Broken Alternative Content:
The user can be notified when the user agent cannot render alternative content (e.g. when captions are broken). (Level AAA)
- Intent of Success Criterion 1.2.4:
Users who have chosen to have alternative content presented to them greatly appreciate understanding whether a non-working requests is due to a source error, user error, or merely a delay. Users who lack this information may incorrectly conclude that a particular site is not accessible to them, or may waste time either waiting for content or attempting to find a non-existent problem in their browser or configuration. Note that it is generally recommended that this type of notification NOT require user response, so as not to interrupt the user's experience.
- Examples of Success Criterion 1.2.4
- _____ has images turned off and replaced by their alt text. When alt text is missing, an error icon is presented in its place.
- _____ is watching videos embedded in a Web page. The browser enables a Captions button when it detects that a caption stream is available. The user clicks this to turn on display of captions, but the browser finds the caption stream is invalid. Instead of merely showing blank space, it displays a small message or icon in the caption area to inform the user that the requested captions cannot be displayed.
- Related Resources for Success Criterion 1.2.4:
- Success criterion 1.1.3 requires that the user be informed when the document indicates that alternative content is present, but the browser may not know that the alternative content is broken until the user actually attempts to render or play it.
Implementing
Guideline 1.3 - Provide highlighting for
selection, keyboard focus, enabled elements, visited links.
Summary: The user can visually distinguish selected, focused, and enabled items, and recently visited links (1.3.1), with a choice of highighting options that at least include foreground and background colors, and border color and thickness (1.3.2).
1.3.1 Highlighted Items:
The user can globally specify that the following be highlighted so that each class is uniquely distinguished. It is not the intention that all recognized enabled elements be uniquely distinguished, just that they be distinguished from disabled elements. (Level A)
- (a) selection
- (b) active keyboard focus (indicated by focus cursors and/or text cursors)
- (c) recognized enabled elements
- (d) elements with alternative content
- (e) recently visited links
- Intent of Success Criterion 1.3.1:
Users need to be able to easily discover what web content they can interact with. Users with low vision need to be able to highlight selection, content focus, enabled elements and links (including recently visited links) in order to successfully discover and interact with the web content.
Note: In addition to these required categories, it is recommended that user agents also allow the user to highlight the active viewport, even when it is a frame or similar within the active window, which makes it much easier for the user to visually locate the active focus.
Note: Platform conventions will dictate whether or not an inactive keyboard focus (keyboard focus in an inactive viewport) is visually indicated by an inactive cursor.
Note: the definition of visited and unvisited links is up to the user agent. In some cases it might be links visited during the current session, or in other cases links visited in the browser's history until that is cleared.
- Examples of Success Criterion 1.3.1:
- A web site uses styles to override visited link color. A low vision user wants to know what links have yet to be explored. The user agent provides a dialog box for setting overrides to author-selected link colors.
- An author has created a web site with CSS styles that removes the content focus outline. The user agent provides a dialog box for setting overrides to authors CSS focus outline declaration.
- Related Resources for Success Criterion 1.3.1:
- UAAG 1.3.2 Highlighting Options, describes user options to configuring how these categories are highlighted
- UAAG 2.1.? Keyboard Focus requires every window have an active or inactive keyboard focus at all times
- UAAG 1.8.8 for highlighting a viewport
- UAAG 1.8.9 for highlighting an active window
1.3.2 Highlighting Options:
When highlighting classes specified by 1.3.1 Highlighted Items and 1.3.3 Highlighted Input Controls, the user can specify highlighting options that include at least: (Level A) [@@Editor's Note: Review for editorial rewording to compensate for a reference to an SC the reader hasn't read yet.@@ ]
- (a) foreground colors,
- (b) background colors, and
- (c) borders (configurable color, style, and thickness)
- Intent of Success Criterion 1.3.2:
A low vision user needs control over what visual properties work best for
highlighting. These include foreground colors, background colors, and
visual borders (with the same configurable range as the operating environment's conventional selection utilities)
- Examples of Success Criterion 1.3.2:
- A low vision wants to know where the text boxes are on a web form. The
user wants to set a thick black border around all text boxes. The user
agent provides a dialog box allowing the user to override any author
settings.
- Alex has low vision and sometimes has difficulty distinguishing the fields on web forms. He chooses to have all form fields displayed with a yellow background and outlined with a thick black border.
- Related Resources for Success Criterion 1.3.2:
1.3.3 Highlighted Input Controls:
The user can have the following highlighted when they are recognized:
(Level AA)
- (a) enabled controls that take input (e.g. push buttons, radio buttons, check boxes, and text input fields, but not groupings or static text and images) regardless of whether they are read-write or read-only, and
- (b) elements with scripted input handlers (e.g. images or text ranges that have onClick or onKeyPress events) regardless of whether the current state allows them to operate.
- Intent of Success Criterion 1.3.3:
When a user looks at a page they often want to quickly find the control they need to accomplish their task, yet in some pages the controls may be "buried" amid a large amount of other content, or may be styled to make it very hard to distinguish from other content. This can be particularly difficult for people with visual impairments, who may not be able to easily distinguish visual differences that may be subtle or obvious to users with average vision. It can also be a problem for people with some cognitive impairments, who may have difficulty distinguishing between items with similar or non-standard appearance. The ability to have these items visually distinguished can greatly help reduce the amount of time or number of commands they need to use examining a page. This success criterion works in conjunction with 1.3.1 Highlighted Items, which ensures highlighting of several other classes of information, and with 1.3.2 Highlighting Options, which ensures that the user can
customize the highlighting to meet their visual or cognitive needs.
- Examples of Success Criterion 1.3.3:
- Binh gets easily frustrated when he cannot locate the buttons and links on a page, usually because they don't have the standard appearance he's used to. By turning on the option to have all links appear in bright purple, and all push buttons and the like drawn with a bright purple border, he can easily scan the page and find the items he's looking for.
- Related Resources for Success Criterion 1.3.3:
- 1.1.3 Identify Presence of Alternative Content (Level A) requires items with alternative content to be highlighted.
- 1.3.1 Highlighted Items (Level A) requires highlighting of additional classes, including the selection, the active keyboard focus, and visited and unvisited links.
- 1.3.2 Highlighting Options (Level A) requires the user be able to customize the appearances of these highlights.
Implementing
Guideline 1.4 - Provide text configuration.
Summary: The user can control text font, color, and size (1.4.1), including whether all text should be the shown the same size (1.4.2).
1.4.1 Configure Rendered Text:
The
user can globally set any or all of the following
characteristics of visually rendered text content, overriding any specified by the author or user agent defaults: (Level A)
- (a) text scale (i.e. the general size
of text) ,
- (b) font family,
- (c) text color (i.e. foreground and
background),
- (d) line spacing, and
- (e) character spacing.
- Intent of Success Criterion 1.4.1:
Users need to able to access a wide range of
font sizes, styles, colors, and other attributes in order to find the
combination that works best for their particular needs. For example,
some users want to increase font size to make text more legible, while
other users want to reduce the font size to decrease the need to scroll the content. In providing these preferences, it is important to avoid making assumptions. For example, some users want to reduce the font size to decrease the need to scroll the content.
- Examples of Success Criterion 1.4.1:
- Lee has low vision from albinism and has difficulty with screen resolution and brightness. She chooses to have all text displayed in Palatino font, with white text on a black background, and at least 16 points tall. The serif Palatino font has character spacing that resolves better for her vision, while the white on black reduces glare and the larger size allows her to distinguish fine detail more clearly.
- Tomas has extremely low vision and chooses to have his browser display all text the same size, and sets that size as large as he can without making the letters too tall for his screen. He chooses not to have headings be proportionately larger than normal text because that would make them taller than his screen and so unreadable.
- Browser A supports only 3 font sizes: Small, Medium, and Large. Lee, who has low vision, needs to use a font size of 16 pt, which is between the medium and large sizes. Browser A provides an option to override the 3 font sizes with the operating system font range, so that Lee can select the 16 pt font size she needs.
- Related Resources for Success Criterion 1.4.1:
1.4.2 Preserving
Size Distinctions:
The user can specify whether or not distinctions in the size of rendered text are preserved when that text is rescaled (e.g. headers continue to be larger than body text). (Level A)
- Intent of Success Criterion 1.4.2:
The relative size of text provides visual cues that help in understanding and navigating web content and because some content may be authored in a way that would make it difficult or impossible to understand when if font distinctions were hidden. For example, headlines in a larger font than the body text. Users who set preferences to enlarge or reduce the text size need to have these visual cues preserved.
- Examples of Success Criterion 1.4.2:
Lee finds text easiest to read at 16 pt Palatino, but can chooses to have her browser display all in the Palatino font and at least 16 pt in size. She needs the headlines to scale proportionally (e.g. 24 pt) in order to preserve headline prominence.
- Related Resources for Success Criterion 1.4.2:
Implementing
Guideline 1.5 - Provide volume configuration.
Summary: The user can adjust the volume of each audio track relative to the global volume level (1.5.1).
1.5.1 Global Volume:
The user can independently
adjust the volume of all audio tracks, relative to the global volume level set
through operating environment mechanisms. If the global setting is mute, the user agent may override a global mute on explicit user request that cautions the user about the implication. (Level A)
- Intent of Success Criterion 1.5.1:
User agents can render audio tracks from a variety sources, and in
some cases, multiple audio tracks may be present on a single page.
Users should be able to globally set the volume of audio tracks, rather
than having to adjust the volume of each audio track being played.
- Examples of Success Criterion 1.5.1:
- An operating system provides a master audio volume control that
applies to all audio tracks rendered within the environment, including
the user agent. The user may define a default volume level through a
preferences dialog that is retained across sessions.
- A user encounters a page with two advertisements and one video which
begins playback on page load complete. A global mute command, supported
via a mute key on the user's keyboard, allows the user to immediately
silence the playing audio tracks.
- Related Resources for Success Criterion 1.5.1:
Implementing
Guideline 1.6 - Provide synthesized speech configuration.
Summary: If synthesized speech is produced, the user can specify speech rate and volume (1.6.1), pitch and pitch range (1.6.2), and synthesizer speech characteristics like emphasis (1.6.3) and features like spelling (1.6.4).
1.6.1 Speech Rate, Volume, and Voice:
If synthesized speech is produced, the user can specify the following: (Level A)
- (a) speech rate,
- (b) speech volume (independently of
other sources of audio), and
- (c) voice, when more than one voice option is available
1.6.2 Speech Pitch and Range:
If synthesized speech is produced, the user can specify the following: (Level AA) :
- (a) pitch (i.e. the
average frequency of the speaking voice), and
- (b) pitch range (i.e.
specifies a variation in average frequency),
1.6.3 Advanced Speech Characteristics:
The
user can adjust all of the speech characteristics offered by the speech
synthesizer. (Level AAA)
- Intent of Success Criterion 1.6.1, 1.6.2, 1.6.3:
The objective of these success criteria is to allow the user to customize the specified speech characteristics to settings that allow the user to perceive and understand the audio information.
Users may need to increase the volume to a level within their range of perception for example. Users may also wish to increase the rate of synthesized speech presentation because they can understand it at a rate faster than the default setting of the user agent.
Success criterion 1.6.1 covers the characteristics that users most commonly need to adjust and that are adjustable in most technologies, while success criterion 1.6.2 covers characteristics that are less widely altered and less widely supported.
- Examples of Success Criterion 1.6.1, 1.6.2, 1.6.3:
- A telephone-based web browser starts reading back a web page. The user can press a key to increase the rate at which the information is read back. Similarly, the user may be using this telephone browser in a noisy environment such as a crowded subway. With a key press the user can quickly increase the volume of the speech being heard.
- Randy has a hearing disability where speech at lower pitches is difficult to hear. He is using an audio browser that reads web pages back to him. He issues a voice command saying "raise pitch" and the overall pitch of the synthetic speech is increased.
- Related Resources for Success Criterion 1.6.1, 1.6.2, 1.6.3:
1.6.4 Synthesized Speech Features:
If synthesized speech is produced, the following features are provided: (Level AA)
- (a) user-defined extensions to the
synthesized speech dictionary,
- (b) "spell-out", where text is spelled
one character at a time, or according to language-dependent pronunciation
rules,
- (c) at least two ways of speaking numerals:
one where numerals are spoken as individual digits and punctuation (e.g. "one two zero three point five" for 1203.5 or "one comma two zero three point five" for 1,203.5), and
one where full numbers are spoken (e.g. "one thousand, two hundred
and three point five").
- (d) at least two ways of speaking
punctuation: one where punctuation is spoken literally, and one
where punctuation is rendered as natural pauses.
- Intent of Success Criterion 1.6.4:
The synthetic speech presentation of text can be difficult to understand at times. Success criteria here are aimed at giving the user the ability to adjust the way in which the speech synthesizer presents text to improve understandability.
- Examples of Success Criterion 1.6.4:
- Penny is using a browser that reads web pages to her and reviewing her most recent banking transactions. She has configured a setting in the speech configuration for the browser to have currency spoken as currency instead of digits. She hears a transaction read as "Deposit, two hundred fifty five dollars," as a result of this change.
- The speech synthesizer incorrectly pronounces technical terms employed in George's organization. These terms are consistently mispronounced in a way that makes it difficult for the George to distinguish them, even though they are instantly distinguishable when displayed as text. A dictionary allows the user to enter a spelling of the name that produces the correct pronunciation from the synthetic speech.
- A speech synthesizer is repeating a phone number. Penny wishes to easily copy this number so switches to a mode where each digit is spoken as a unique word e.g. five, five, five and so on.
- Related Resources for Success Criterion 1.6.4:
Implementing
Guideline 1.7 - Enable Configuration of Style Profiles.
Summary: The user agent shall support user style profiles (1.7.1) and the user can choose which if any user-supplied (1.7.2) and author-supplied (1.7.3) style profiles to use.
1.7.1 Support User Style Profiles:
User agents that support a mechanism for authors to supply style profiles shall also provide an equally effective mechanism for users to supply profiles. (Level A)
1.7.2 Apply User Style Profiles:
The user can turn on the use of user style profiles and for every user style profile defined, the user can choose whether or not it should be applied to: (Level A)
- (a) the current page, or
- (b) all pages on specified web sites, or
- (c) all pages.
1.7.3 Author Style Sheets:
The user can turn off the use of author style profiles, and for every author style sheet defined the user can choose whether or not it should be applied to: (Level A)
- (a) the current page, or
- (b) all pages for which it is defined.
- Intent of Success Criterion 1.7.1, 1.7.2 & 1.7.3:
CSS stylesheets allow for extensive customization of the rendering of web content. Such customization is frequently used to make web content accessible to a wide range of user needs. These success criteria ensure that users of web browsers can fully take advantage of the stylesheets offered by web authors or that the users have created.
- Examples of Success Criterion 1.7.1, 1.7.2 & 1.7.3:
- A user finds yellow text on a black background easiest to read. When a web site is loaded, the user agent provides a menu where the user can select between several stylesheets that the web author has created for the web site. The user selects a stylesheet named yellow on black from a menu in the user agent listing all available stylesheets. The web content is then rendered using this stylesheet.
- On a shared computer a web site is rendered with black text on a white background that is normally in full color. The user agent provides a menu where the user can de-select a user-defined stylesheet has been applied to the web page and the user easily disables this stylesheet. The web site is now rendered in full color.
- Related Resources for Success Criterion 1.7.1, 1.7.2 & 1.7.3:
1.7.4 Save copies of style profiles:
The user can save copies of the style profiles referenced by the current page, so that they can edit and load them as user style
profiles. (Level AA)
- Intent of Success Criterion 1.7.4:
TBW
- Examples of Success Criterion 1.7.4:
- Related Resources for Success Criterion 1.7.43:
Implementing
Guideline 1.8 - Help users to use and orient within windows and viewports.
Summary: The user agent provides programmatic and visual cues to keep the user oriented. These include highlighting the viewport (1.8.1), keeping the focus within the viewport (1.8.2), resizing the viewport (1.8.3), providing scrollbar(s) that identify when content is outside the visible region (1.8.4) and which portion is visible (1.8.11), and restoring the focus and point of regard when the user returns to a previously viewed page (1.8.5). Additionally, the user can specify that all view ports have the same user interface elements (1.8.10), if and how new viewports open (1.8.6), and whether the new window automatically gets focus (1.8.7). The user can also close any open window or tab (1.8.9).
1.8.1 Highlight Viewport:
The viewport with the input focus (including nested viewports and their containers) is highlighted, and the user can customize attributes of the highlighted mechanism, including, but not limited to, shape, size, stroke width, color, and blink rate (if any). (Level A)
- Intent of Success Criterion 1.8.1:
When a user agent presents content using multiple viewports, users
benefit from a clear indication of which viewport has focus. Simply
relying upon text foreground and background colors to indicate focus
may not provide sufficient, visually perceivable indication for users
with low vision. Highlighting of viewport frames using both color,
with sufficient contrast, and increase in viewport border thickness
can provide multiple visual cues that indicate focus.
- Examples of Success Criterion 1.8.1:
- A music Web site allows the user to select which of the top 10 songs
are available for listening. Each song is presented in a graphical
viewport providing a music player. Using a keyboard based screen
magnification tool, a low vision user tabs between songs, with the
currently selected player viewport highlighted with a thick, yellow
border against a dark gray background.
- Related Resources for Success Criterion 1.8.1:
1.8.2 Move Viewport to Selection and Focus:
When a viewport's selection or input focus changes, the viewport's content moves as necessary to ensure that the new selection or input focus location is at least partially in the visible portion of the viewport. (Level A)
- Intent of Success Criterion 1.8.2:
When content is presented within a viewport and the content extends
horizontally or vertically beyond the visible bounds of the viewport,
the user must be able to move to a selectable element or elements
which may be out of view, and to have the selected content
automatically move into view. For keyboard based users and users of
screen magnification tools, this allows users an efficient means to
view selected content without having to utilize scrolling controls to
locate and view the selection.
- Examples of Success Criterion 1.8.2:
- A screen magnification user is performing a spell check of a blog
posting that is contained within a scrollable viewport. The text of
the blog posting exceeds the vertical size of the viewport. The
blogging software provides a key to move to the first, and then any
subsequent, unrecognized words. With two unrecognized words in the
posting, the user ignores the first selected word, and presses the
keystroke to move to the next which is currently out of view in the
last sentence of the posting. As the key is pressed, the viewport
scrolls to show the selected word.
- A user of a screen reader is showing a sighted colleague how to
complete a registration form contained within a viewport. The form
exceeds the vertical bounds of the viewport, requiring vertical
scrolling to view the complete form content. As the screen reader
completes each form entry and presses the tab key, the next form
control in the tab order scrolls into view if it is not already
visible in the viewport.
- Related Resources for Success Criterion 1.8.2:
1.8.3 Resize Viewport:
The user can make viewports
resizable, within the limits of the display, overriding any values
specified by the author. (Level A)
- Intent of Success Criterion 1.8.3:
If a graphical viewport contains content that exceeds the dimensions
of the viewport, users should have the option to increase the size of
the viewport to allow the full image to be displayed without
scrolling, within the limits of the physical display screen. This
benefits keyboard users who may find it difficult to scroll content
and users with cognitive or learning disabilities whose understanding
of the content is aided by being able to view the complete image.
- Examples of Success Criterion 1.8.3:
- A viewport is used to display an image depicting an organization
chart. A user with a learning disability has difficulty maintaining a
mental representation of the organizational linkages for items out of
view. In order to facilitate their understanding of the organization,
the user drags the sizing icon on the corners of the viewport to allow
the entire chart to be displayed.
- Related Resources for Success Criterion 1.8.3:
1.8.4 Viewport Scrollbars:
Graphical viewports include scrollbars if the rendered content
(including after user preferences have been applied) extends beyond the
viewport dimensions, overriding any values specified by the
author. (Level A)
- Intent of Success Criterion 1.8.4:
When rendered content exceeds the horizontal or vertical bounds of
a graphical viewport, scrollbars provide a visible indication that not
all of the rendered content is currently visible within the viewport.
The scrollbars provide indication to users who may not be able to
otherwise recognize that the rendered content is not fully visible.
- Examples of Success Criterion 1.8.4:
- A Web site presents a recipe within a viewport, and the length of the
recipe exceeds the vertical and horizontal dimension of the viewport,
though the step by step graphical depiction of the recipe does not
make this obvious. A user following the recipe, uses the scroll bar to
recognize that additional steps may be present, and scrolls them into
view.
- Related Resources for Success Criterion 1.8.4:
1.8.11 Indicate Viewport Position:
The user can determine the viewport's position relative to the full extent of the rendered
content. (Level A)
- Intent of Success Criterion 1.8.11:
This criteria targets the ability for a user to easily understand where they are located relative to the total content available for rendering and the amount of content relative to the total being displayed.
- Examples of Success Criterion 1.8.11:
- A user navigates to a lengthy web page and begins paging through the content. A scroll bar visually indicates the position within the content as the user pages and also that with each paging action only a small portion of the content is being rendered. Another user accesses this web page with a screen reader and has the percentage that the page is scrolled communicated by the screen reader because the user agent makes information from the scroll bar available programmatically.
- Related Resources for Success Criterion 1.8.11:
1.8.5 Viewport History:
For user agents that implement a viewport history mechanism (e.g. "back" button), the user can return to any state in the viewport history, restoring the prior point of regard, input focus and selection.(Level A)
1.8.6 Open on Request:
The user can specify whether author content can open new top-level viewports (e.g. windows or tabs). (Level A)
1.8.7 Do Not Take Focus:
If new top-level viewports (e.g. windows or tabs) are configured to open without explicit user request, the user can specify whether or not top-level viewports take the active keyboard focus when they open. (Level AA)
- Intent of Success Criteria 1.8.5, 1.8.6 & 1.8.7:
Unexpected focus and viewport changes can be disorienting for all users, requiring time and effort for the user to orient to the change. These success criteria are intended to allow the user to be in control of when viewport changes happen so the user can orient to the changes in a predictable fashion.
- Examples of Success Criteria 1.8.5, 1.8.6 & 1.8.7:
- A web page is loaded in the browser that triggers a secondary page (typically known as a pop-up) to open. The user agent presents the user with the initial page requested and an alert that additional content is available. The user can choose to have this pop-up content shown or not, remaining in control of what is displayed in the user agent's viewport. A user agent may also be configured so that pop-ups do open automatically because the user has chosen to automatically have this content available. The user has a setting however to configure pop-ups such that they open in the background. Hence when visiting a web page with this secondary content, focus remains in the primary viewport with the initial page content requested. The user agent alerts the user that secondary content is available in another viewport and the user can activate this viewport on request, perhaps with a click on the notification mechanism.
- Related Resources for Success Criteria 1.8.5, 1.8.6 & 1.8.7:
- 3.4.1 Avoid unpredictable focus
1.8.10 Same UI:
The user can specify that all top-level viewports (e.g. windows or tabs) follow the current user interface configuration. (Level AA)
- Intent of Success Criterion 1.8.10:
Users orient themselves to a browsing environment with a variety of techniques. This success criteria is designed to ensure that the user does not have to learn multiple strategies to use the browsing viewport.
- Examples of Success Criterion 1.8.10:
- Robert uses magnification software. After setting up his user agent, he knows that web content begins predictably one inch from the top of the window, so he can configure his magnification software to present content starting at that location.
- Courtney has difficulty understanding and using complex user interfaces. She has worked with her sister to set up her browser to have only a few of the most common browser controls displayed and she knows to expect them on every browser window.
- Related Resources for Success Criterion 1.8.10:
- This is relies on saving and restores settings in 2.7.4
Implementing
Guideline 1.10 - Provide alternative views.
Summary: The user can view the source of content (1.10.1), or an "outline" view (1.10.2), and may specify the elements to be used for the outline view (1.10.3).
1.10.1 Source View:
The user can view all source text that is available to the user agent. (Level AA)
- Intent of Success Criterion 1.10.1:
The source view is the ultimate fallback when the browser cannot
properly render some content, or when the user cannot take advantage of
the content as rendered or using the mechanisms provided.
- Examples of Success Criterion 1.10.1:
- When the content author failed to provide alt text or longdesc for an
image, the user can, as a last resort, try to get some information by
examining the source to see the image's URI, class, and similar attributes.
- When the user wants to create a customized style sheet for a Web site,
they need to identify the style, class, and id attributes it uses.
- Related Resources for Success Criterion 1.10.1:
1.10.2 Outline View:
An
outline view of rendered content is provided,
composed of labels for important structural elements (e.g. heading text,
table titles, form titles, and other labels that are part of the content).
(Level AA)
Note: The outline constitutes the important structural elements for the user (See 1.10.3). A label is defined by each markup
language specification. For example, in HTML, a heading
(H1
-H6
) is a label for the section that follows it,
a CAPTION
is a label for a table, and the title
attribute is a label for its element.
- Intent of Success Criterion 1.10.2:
Outline views can help all users get a simplified view or overview of a
document. They are particularly useful for users with memory or
cognitive disabilities, as well as users with serial access to content
or who navigate sequentially. The outline view is a type of summary view
and should reduce orientation time. A navigable outline view will add
further benefits for these users.
- Examples of Success Criterion 1.10.2:
- A Web browser provides an optional panel displaying a hierarchical list
of the headers and tables in the current document.
The user is able to expand or shrink portions of the outline view for
faster access to important parts of content.
- A Web browser provides a command to use CSS display and visibility
properties to hide all content other than important structural elements
such as titles, headings, and table headings.
- A Web browser provides a structured view of form controls (e.g. those
grouped by LEGEND or OPTGROUP in HTML) along with their labels.
- Amaya table of contents view @@ Editors' Note: Insert photo@@
This image shows the table of contents view provided by Amaya [AMAYA].
This view is coordinated with the main view so that users may navigate
in one viewport and the focus follows in the other. An entry in the
table of contents with a target icon means that the heading in the
document has an associated anchor.
- Related Resources for Success Criterion 1.10.2:
- This Success Criterion (1.10.2) deals with making document structure
perceivable to the user. It is complimentary to Guideline 4.7 which
deals with making document structure navigable.
1.10.3 Configure
Elements for Outline View:
The user can configure the set of important elements for the outline view, including by element type (e.g. headers). (Level AAA)
- Intent of Success Criterion 1.10.3:
Sometimes authors will visually convey relationships between elements by spatially grouping them, by giving them the same coloration or background, and so forth. Users may not be able to perceive those attributes, such as when using a screen reader, or when strong magnification makes it difficult to make a mental model of the screen layout. In those cases the user agent can assist by providing a view of the data that groups elements that that user agent perceives as implying relationships.
- Examples of Success Criterion 1.10.3:
- Jane uses a mobile device (and is often situationally impaired) and often encounters tables laid out using floating DIV elements with specific class names denoting the visual styling. In this case Jane cannot use the cursor keys to move around these tabular layouts having instead to use the tab key to move sequentially left-to-right top-to-bottom. Jane's browser allows her to configure important elements and so she can pick out the classes associated with thes element, and therefore use the cursor key to move logically through columns or rows.
- Related Resources for Success Criterion 1.10.3:
Implementing
Guideline 1.11 - Provide element information.
Summary:The user agent presents information about content relationships (e.g. form labels, table headers)(1.11.1), and extended link information (e.g. title, internal vs. external) (1.11.2)
1.11.1 Access Relationships:
The user can access explicitly-defined relationships based on the user's position in content (e.g. show form control's label, show label's form control, show a cell's table headers). (Level A)
- Intent of Success Criterion 1.11.1:
Some users have difficulty perceiving, remembering, or understanding the relationships between elements and their contexts. HTML controls and elements are sometimes grouped together to make up a composite control; certain elements relate to others in a recognizable manner, such as relationships with 'id' attributes and child elements. This is the case with Ajax widgets and with form elements. By making sure the user can be informed about these relationships means that, say, visually disabled users can better understand these relationships even if the elements are not adjacent on the screen or the DOM.
- Examples of Success Criterion 1.11.1:
- John has low vision and uses a screen magnifier to access his Browser. When interacting with tables and spreadsheets John has to move the viewport of the magnifier to understand the row and column titles of the cell with which he is interacting. This takes additional time and effort and is therefore frustrating. John has just purchased a new Browser because it presents the row and column titles when he hovers over a cell - this makes him much more productive at his accounting job.
- Related Resources for Success Criterion 1.11.1:
- WAI-ARIA
- UAAG 2.7.3 Location in Hierarchy
1.11.2 Extended Link
Information:
The user agent provides for each link:
(Level AAA)
- link title
- technology type (of the linked Web resource)
- internal/external (whether the link
is internal to the resource e.g. the link is to a target in the same
Web page)
- Intent of Success Criterion 1.11.2:
Users who use screen readers need to be able to easily discover information about a link, including the title of the link, whether or not that link is a webpage, PDF etc. and whether the link goes to a new page or a different location in the current page, in order to navigate Web content more quickly and easily.
- Examples of Success Criterion 1.11.2:
- Robert, who uses a screen reader, needs to know whether a given link will automatically open in a new page or a new window. The browser indicates this information so he can discover it before he makes a decision to click on a link.
- Maria has an attention disorder, new windows opening are a large distraction. She needs to know whether a given link will automatically open in a new page or a new window. The browser indicates this information so she can decide not to follow a link that opens a new window.
- Related Resources for Success Criterion 1.11.2:
PRINCIPLE 2. Ensure that the user interface is
operable
Summary: Users can operate all functions (2.1.1), and move focus (2.1.2, 2.1.3) using just the keyboard. Users can activate important or common features with shortcut keys, (2.1.8), override keyboard shortcuts in content and user interface (2.1.4), escape keyboard traps (2.1.5), specify that selecting an item in a dropdown list or menuoes not activate that item or move to that new web page (2.1.6) and use standard keys for that platform (2.1.7).
2.1.1 Keyboard Operation:
All
functionality can be operated via the keyboard using sequential or direct
keyboard commands that do not require specific timings for individual
keystrokes, except where the underlying function requires input that depends
on the path of the user's movement and not just the endpoints (e.g. free
hand drawing). This does not forbid and should not discourage providing mouse
input or other input methods in addition to keyboard operation. (Level A)
- Intent of Success Criterion 2.1.1:
A user has many ways to input information into a computer or device, including mouse, keyboard, gesture, and speech. The keyboard paradigm is the most universal interface for text input - even devices that do have a keyboard (like mobile phones) support a software interface for them. A user should be able to navigate, read and use all of the web page or application without needing to use a mouse. Some users do not use a mouse, others can only use a pointing device that uses the keyboard API. Therefore, ensure that the user can interact with enabled components, select content, navigate viewports, configure the user agent, access documentation, install the user agent, and operate user interface controls, all entirely through keyboard input.
User agents generally support at least three types of keyboard operation:
- 1. Direct (e.g. keyboard shortcuts such a "F1" to open the help menu; see checkpoint 11.4 for single-key access requirements),
- 2. Sequential (e.g. navigation through cascading menus), and
- 3. Spatial (e.g. when the keyboard is used to move the pointing device in two-dimensional visual space to manipulate a bitmap image).
User agents should support direct or sequential keyboard operation for all functionalities. Furthermore, the user agent should satisfy this checkpoint by offering a combination of keyboard-operable user interface controls (e.g. keyboard operable print menus and settings) and direct keyboard shortcuts (e.g. to print the current page).
- Examples of Success Criterion 2.1.1 :
- The user must be able to do the following through the keyboard alone (or pointing device alone or voice alone):
- Select content and operate on it. For example, if the user can select rendered text with the mouse and make it the content of a new link by pushing a button, they also need to be able to do so through the keyboard and other supported devices. Other operations include cut, copy, and paste.
- Set the focus on viewports and on enabled elements.
- Install, configure, uninstall, and update the user agent software.
- Use the graphical user interface menus. Some users may wish to use the graphical user interface even if they cannot use or do not wish to use the pointing device.
- Fill out forms.
- Access documentation.
- An author uses the CSS overflow property to constrain the size of a block of content. The user agent provides scroll bars to display text that overflows the container. The user can use the keyboard to enter the element and operate the scrollbars to visually access the content. The user can return to the main flow of the next element on the page (see SC 2.1.3)
- The author codes a volume control slider widget. The user can focus on the widget, and using the arrow keys to increase or decrease the volume, and then hit another key to move to the next element in the content.
- Cade has low vision, and can't identify an icon so wants to be able to read its alternative text. Most users would be able to hover the mouse over the icon and have its alternative text displayed as a pop-up ortooltip, but since Cade does not use a mouse, he can activate a command that allows him to use the tab key to move the keyboard focus to elements that have alternative content. Then, when he tabs to the icon, the browser may automatically display the "hover" tooltip, or allow him to press a key to have it displayed.
- Omar is a speech-recognition user who cannot use his hands to control his computer. It is much easier for him to use keyboard shortcuts then click on an icon in a new program. He needs to be able to see tooltips to discover keyboard shortcuts without having to use the mouse.
- Related Resources for Success Criterion 2.1.1:
- Microsoft Keyboard accessibility document
- Apple keyboard
- Unix
2.1.2 Keyboard Focus (former 1.9.1):
Every viewport
has an active or inactive keyboard focus at all times. (Level A)
- Intent of Success Criterion 2.1.2:
Both the user and some types of assistive technology need to know what will be affected by any keyboard input, so it's important that they be able to tell which window, viewport, and controls have the keyboard focus at any time. This applies whether window and viewport are active (active keyboard focus) or inactive (inactive keyboard focus). Even when a window is inactive, it can be affected by simulated keyboard input sent by assistive technology tools. Active keyboard focus is indicated to the user by focus cursors and text cursors, as required by Guidelines 1.3, and made available to assistive technology, as required by Success Criterion 4.1.6.
- Examples of Success Criterion 2.1.2:
- Alan launches a web browser and navigates to a web page. Initially the keyboard focus is treated as being on the entire document, and that is exposed to assistive technology, but there is no visible cursor. When he presses the tab key, the focus moves to the first link on the web page, and a cursor in the form of a dotted rectangle appears around that link.
- Ellen launches a web browser and navigates to a web page that has an enabled edit field. The browser places the keyboard focus on the edit field, so she can immediately start entering text, and it's location is shown using a text cursor (usually a vertical line or i-beam). As Ellen types, the text cursor moves to show where the next character will appear. If she activates another window, the browser may hide the cursor in the now inactive window, but its location is still available to assistive technology.
- Raymond has low vision. As the keyboard focus moves from one control to another, or one window to another, his screen enlarger utility detects the focus change and pans its viewport to keep the focus location visible.
- Related Resources for Success Criterion 2.1.2:
- Guideline 1.3 (Provide highlighting for selection, active keyboard focus, enabled elements, visited links) ensures that the focus location is made visible to users.
- Success Criterion 4.1.6 (Properties) ensures that the focus location is available to assistive technology.
2.1.3 Viewport Navigation (former 1.9.2 & 1.9.4):
The user can move the active keyboard focus to any viewport. (Level A)
[@@Editor Note: Delete 2.1.3 to merge intent and examples with 2.2.2 and fix summary (2012/01/20)@@]
- Intent of Success Criterion 2.1.3:
Each viewport has a keyboard focus (per 2.1.2), but it's also important that the user be able to navigate to that viewport, making its keyboard focus become the active keyboard focus. This navigation can be between viewports within the application, or between windows or applications. This includes the user agent's user interface, extensions to the user interface (e.g. add-on), content, and plug-ins handling content.
- Examples of Success Criterion 2.1.3:
- Ruth is working in her web browser, where one document window (viewport) is active (has the active keyboard focus). When she switches to her word processor, the web browser's window and its keyboard focus become inactive, and it hides its cursor. When she switches back to the browser window, it reactivates that viewport, its keyboard focus becomes active again, and its cursor reappears in the same location as when she switched to a different application.
- A developer creates an extension to a user agent that allows the user to add notes about each web page being visited. A user can press a shortcut key to move focus to the user interface of this extension and interact with the functionality offered by the extension. Similarly, the user presses another key to move focus back to the main viewport for the user agent in the same location as when she moved to the plugin.
- Related Resources for Success Criterion 2.1.3:
- 2.2.1 ensures that the user can navigate to elements within the viewport.
2.1.4 Specify preferred keystrokes (former 2.1.2):
The user can override any keyboard shortcut including recognized author supplied shortcuts (e.g. accesskeys) and user interface controls, except for conventional bindings for the operating environment (e.g. arrow keys for navigating within menus). (Level A)
- Intent of Success Criterion 2.1.4:
Some users may be able to hit certain keys on the keyboard with greater ease than others. Assistive technology software typically has extensive keyboard commands as well. The goal of this SC is to enable the user to be in control of what happens when a given key is pressed and use the keyboard commands that meet his or her needs.
- Examples of Success Criterion 2.1.4:
- Laura types with one hand and finds keys on the left side of the keyboard easier to press. She browses to a web page and notices that the author has assigned access keys using keys from the right side of the keyboard. She opens a dialog in the user agent and reassigns the access keys from the web page to the left side of the keyboard home row.
- Elaine's screen magnification program uses alt+m to increase the size of the magnified area of the screen. She notices that in her web browser, alt+m is a hotkey for activating a home button that stops her from being able to control her magnification software. She opens a hotkey reassignment feature in the user agent, and sets alt+o to be the new hotkey for the home button. Her screen magnification software now works correctly.
- Related Resources for Success Criterion 2.1.4:
2.1.5 No Keyboard Trap (former 2.1.3):
If keyboard focus can be moved to a component using a keyboard interface, then focus can be moved away from that component using only a keyboard interface, and, if it requires more than unmodified arrow or tab keys or other standard exit methods, users are advised of the method for moving focus away. (Level A)The user
agent prevents keyboard traps as follows: (Level A)
(a) in the UI: if keyboard focus can be
moved to a component using the keyboard, then focus can be moved away
from that component using standard sequential keyboard commands (e.g.
TAB key)
(b) in the rendered content: provides a
documented direct keyboard command that will always restore keyboard
focus to a known location (e.g. the address bar).
(c) in the rendered content: provides a
documented direct keyboard command that will always move keyboard focus
to a subsequent focusable element
- Intent of Success Criterion 2.1.5:
Intent: If the user can put focus on an element, that they can remove focus and move on to the next element. This is often a problem with embedded objects. The user agent needs to provide a way to always return to the previous or next element in the content, or a known location, such as the address bar. The user agent also needs to be able to take control back from the embedded object, no matter what it is.
- Examples of Success Criterion 2.1.5:
- The user can press tab to put focus on an embedded object and can press shift-tab to move focus to the previous object and tab to move focus to the next object.
- The user has moved the focus to a toolbar extension that does not relinquish control back to the user agent. The user can press Alt-D to move focus to the address bar.
- The user has moved the focus to an embedded scripted application that was poorly programmed. the user can press alt-N (or any documented key combination) that overrides the scripting and moves the focus to the next element in the content.
- advising from Virtual machine flashing a standard message of how to leave the VM [@@Editors' Note: Finish writing this@@]
- Related Resources for Success Criterion 2.1.5:
- Compound documents
- Other SC in UAAG.
2.1.6 Separate Selection from
Activation (former 2.1.4):
The user can specify that selection is separate from activation (e.g. navigating through a set of radio buttons without changing
which is the active/selected option). (Level A)
- Intent of Success Criterion 2.1.6:
This is a repair function for when an author violates WCAG, but the user still needs to be able to read a page without necessarily activating any controls.
- Examples of Success Criterion 2.1.6:
- when a user opens a drop down menu from the keyboard, they must be able to use the arrow keys to move up and down the list, without triggering an action from the items they are moving past.
- A list of radio buttons where putting the focus on the radio button to read it causes the radio button to be selected. The user should be able to arrow or tab through the list of radio buttons without causing any one to be selected. Selection is a separate discrete operation like spacebar. This overrides any author provided scripting behavior.
- Related Resources for Success Criterion 2.1.6:
- ARIA
- WCAG
- 3.4.2 Avoid Side Effects of Navigation
2.1.7
Follow Text Keyboard Conventions (former 2.1.5):
Views that render text support the standard text area
conventions for the operating environment. (Level A)
- Intent of Success Criterion 2.1.7:
Providing a full set of keyboard inputs allows users to efficiently--or at all--perform necessary tasks, such as
character keys, Backspace/Delete, Insert, arrow key navigation (e.g.
caret browsing), Page Up/Page Down, navigate to start/end, navigate by
paragraph, and shift-to-select mechanism. Making these inputs consistent within and across programs greatly reduces learning curve, cognitive load, and errors.
- Examples of Success Criterion 2.1.7:
- Directional keys, letter keys, and the Enter key function should allow navigation within and activation of drop-down menus.
- Ctrl+C or Command+C should copy selected text to the clipboard, allowing the user to avoid manually retyping, and possibly needing to memorize, large amounts of data.
@@ Editors' Note: comment - what happens when things are not consistent. closing dialog boxes are inconsistent ESC or ALT-F4, might be text area keyboard conventions/controls, not just navigation. @@
- Related Resources for Success Criterion 2.1.7:
2.1.8
Efficient Keyboard Access:
The user agent user interface includes mechanisms to make keyboard access more efficient than sequential keyboard access. (Level A)
- Intent of Success Criterion 2.1.8
:
Let the user access commonly used functions as efficiently as possible. Efficient keyboard navigation is especially important for people who cannot easily use a mouse.
- Examples of Success Criterion 2.1.8:
- The user can open a document by pressing Ctrl+O or Command+O.
- The user can temporarily enlarge the rendered content by pressing Ctrl+Plus, rather than having to invoke a menu, choose a command to display a dialog box, select a tab, etc.
- [@@ Editors Note: include a mobile example @@]
- Related Resources for Success Criterion 2.1.8:
- Links to 1.1. Comply with applicable
specifications and conventions
2.1.9
Allow Override of User Interface Keyboard Commands (former 2.1.10):
The user can override any keyboard shortcut binding for the user agent user
interface except for conventional bindings for the operating environment
(e.g. access to help). The rebinding options must include single-key and
key-plus-modifier keys if available in the operating environment. (Level AA)
- Intent of Success Criterion 2.1.9:
The intent of this success criterion is to ensure that people using a keyboard interface have the ability to remap the user agent's keyboard shortcuts in order to avoid keystroke conflicts with assistive technology, reduce number of keystrokes, use familiar keystroke combinations, and optimize keyboard layout (e.g. for one-handed use). This is important for people with dexterity issues where every keystroke can be time consuming, tiring or painful. It is also important for people using assistive technologies such as screen readers, where many keystrokes are already in use by the assistive technology.
- Examples of Success Criterion 2.1.9:
- Ctrl+f may be a command in a screen reader to read the item with focus and this is also typically a user agent find command. The user agent should allow the user to reassign the find command to a non-conflicting key binding. To allow this level of user control, the user agent could provide a list of user interface features and default keyboard assignments with options for the user to assign new key combinations. User keyboard customizations should be saved similar to other user preferences by the user agent.
- Jim, a one handed keyboardist, needs to map all keys to the left side of the keyboard in order to quickly and comfortably reach the keyboard shortcuts he uses frequently.
- Related Resources for Success Criterion 2.1.9:
Implementing Guideline 2.2 - Provide sequential navigation [new, includes former 2.1.8 and 1.9.8, and a new SC]
[Return to Guideline]
Summary: Users can use the keyboard to navigate sequentially (2.2.3) to all the operable elements (2.2.1) in the viewport as well as between viewports (2.2.2). Users can optionally disable wrapping or request a signal when wrapping occurs (2.2.4).
2.2.1 Sequential Navigation Between Elements [replaces 1.9.8 Bi-Directional and 2.1.8 Keyboard Navigation] :
The user can move the keyboard focus backwards and forwards through all recognized enabled elements in the current viewport. (Level A)
- Intent of Success Criterion 2.2.1:
Sequential keyboard navigation is the most fundamental, universal method of keyboard access. While it can be slower and require more input than other methods (such as direct, structural, or search-based navigation) it is a simpler mechanism that requires very little cognitive load or memorization, and is more consistent across contexts. Users need keyboard access to all viewports and all enabled elements so that they can manipulate them, view them with screen magnifiers, or have them described by screen readers. The ability to move both forward and backward through the navigation order greatly reduces the number of keystrokes and allows the user to more easily recover from mistakes in overshooting a destination.
- Examples of Success Criterion 2.2.1:
- Sooj cannot use a pointing device, so she moves the keyboard focus to the next enabled element by pressing the Tab key, and to the previous enabled element by pressing Shift+Tab. Within list boxes and radio button groups she uses the up and down arrow keys to move to the next and previous items.
- Related Resources for Success Criterion 2.2.1:
2.2.2 Sequential Navigation Between Viewports [new]:
The user can move the keyboard focus backwards and forwards between viewports, without having to sequentially navigate all the elements in a viewport. (Level A)
- Intent of Success Criterion 2.2.2:
It is important for the user to be able to jump directly to the next or previous viewports without having to visit every element in a viewport on the way to the next viewport, because that can add an exorbitant number of navigation commands to operations that should be both easy and efficient.User need keyboard access to all viewports and all enabled elements so that they can manipulate them, view them with screen magnifiers, or have them described by screen readers. The ability to move both forward and backward through the navigation order greatly reduces the number of keystrokes and allows the user to more easily recover from mistakes in overshooting a destination.
- Examples of Success Criterion 2.2.2:
- Sooj cannot use a pointing device, so she moves the keyboard focus to the next pane by pressing F6 or the previous pane by pressing Shift+F6. She moves between tabbed document views by pressing Ctrl+Tab and Shift+Ctrl+Tab.
- Related Resources for Success Criterion 2.2.2:
- See the description of 2.2.1 for background information on the importance of sequential navigation.
2.2.3 Default Navigation Order (former 1.9.9) :
If the author has not specified a navigation order, the default
sequential navigation order is the
document order. (Level A)
- Intent of Success Criterion 2.2.3:
The reason for this success criteria is that browsers will be consistent on the tab order they provide WHEN the content author didn't explicitly define one.It is important for users to have a mental map of where the focus will land when they press the Tab key or use other sequential navigation commands. If the focus jumps in seemingly random fashion, skipping up and down, it becomes impossible to use this method efficiently. It requires the user to stop, find the focus, reorient, and determine whether and in which direction they should proceed every single time they press a navigation key. This is a particular problem for users with some cognitive limitations or whose disability makes input difficult, tiring, or painful. Content authors are expected to define a logical navigation order in their documents, but if they have not specified one, this success criterion ensures the order will at least be consistent between user agents.
- Examples of Success Criterion 2.2.3:
- Alec is filling out an HTML form. Because the form's author has not specified a navigation order using the tabindex attribute, when Alec presses the Tab key the focus moves to the next control in the order they are defined in the underlying HTML. This order is likely to seem logical as long as the author is not using styles to change the order in which which the controls appear on page, but even if that is not the case, Alec will still experience the same order when using different browsers on different computers, and therefore navigating the page can become an accustomed habit and much easier than if the order were to change from one system to the other.
- Related Resources for Success Criterion 2.2.3:
- See Web Content Accessibility Guidelines 2.0 success criterion 2.4.3 Focus Order: If a Web page can be navigated sequentially and the navigation sequences affect meaning or operation, focusable components receive focus in an order that preserves meaning and operability.
2.2.4 Options for Wrapping in Navigation (new) :
The user can prevent sequential navigation from wrapping the focus at the beginning or end of a document, and can request notification when such wrapping occurs. (Level AA)
- Intent of Success Criterion 2.2.4:
Users need a good mental map of the navigation sequence and behavior, and particularly need to know when they have started over again so they can maintain that mental map and not waste time and energy inadvertently revisiting information. This is a greater problem for users who can only perceive a limited region (e.g. having a narrow field of vision, or using a screen magnifier or screen reader) or have limited short-term memory. This also prevents people with mobility issues from having to use extra navigation commands.
- Examples of Success Criterion 2.2.4:
- Betsy is using a screen magnifier that only shows her a single line of text. She's navigating through a long list of unsorted items in a list box, searching for one particular entry which, it turns out, is not in the list. Each time she presses the down arrow she is presented with the next item in the list. This particular list box wraps, so when she has read the final entry and presses the down arrow, she is once again presented with the first entry in the list. Unfortunately, because she is quickly discounting every entry that is not her intended goal, she hasn't memorized the list, and it takes her a long time to realize that she's scrolling through the same set of items again and again. To avoid having this happen again, she can turn on options to prevent wrapping, or have the user agent play a sound or present a message before or as it wraps back to the first item. However, keyboard users who can see the entire screen may very well benefit from having wrapping without being interrupted by a pop-up dialog box, so ideally this behavior should be under the user's control.
- Related Resources for Success Criterion 2.2.3:
Implementing Guideline 2.3 - Provide direct navigation and activation [includes former 2.1.6, 2.1.7, 2.1.11]
[Return to Guideline]
Summary: Users can navigate directly (e.g. keyboard shortcuts) to important elements (2.3.1) with the option of immediate activation of the operable elements (2.3.3). Display commands with the elements to make it easier for users to discover the commands (2.3.2 & 2.3.4). The user can remap the direct commands to their needs (2.3.5).
2.3.1 Direct Navigation to Important Elements (former 2.7.4):
The user can navigate directly to important (structural and operable) elements in rendered content. (Level A)
- Intent of Success Criterion 2.3.1
:
It is often difficult for some people to use a pointing device (the standard method of direct navigation) to move the viewport and focus to important elements. In this case some other form of direct navigation - such as numbers or key combinations assigned to important elements - should be available which can then be accessed via the keyboard or speech control technology.
- Examples of Success Criterion 2.3.1
:
- Mary cannot use the mouse or keyboard due to a repetitive strain injury, instead she uses voice control technology with uses a mouse-less browsing plug-in to her browser. The plug-in overlays each hyperlink with a number that can then be used to directly select it (e.g. by speaking the command "select link 12"). This prevents Mary from having to say the word 'tab' numerous times to get to her desired hyperlink.
- Related Resources for Success Criterion 2.3.1
:
- 2.7.7 configure set of important elements @@ Editor's Note - is this still the right number?@@
2.3.2
Present Direct Commands in Rendered Content (former 2.1.6):
The user can have any recognized direct commands in rendered content (e.g. accesskey, landmark) be presented with their associated elements. (Level A)
- Intent of Success Criterion 2.3.2:
Make it easy to for users to discover or be reminded of keyboard shortcuts and similar commands without leaving the context in which they're working. Easy keyboard access is especially important for people who cannot easily use a mouse. An example of this is mouseless browsing. Some users have problems controlling the mouse and/or the keyboard. Therefore users often find control by speech recognition to be advantageous. In this case it is much more efficient for navigation and activation selection points to be both viewable by the user and controllable by their assistive technology.
- Examples of Success Criterion 2.3.2:
- Fiona uses an audio browser. When the system reads form controls in the rendered content, it reads the label of the form followed by the accesskey (e.g., "name alt plus n").
- Mary cannot use the mouse or keyboard due to a repetitive strain injury, instead she uses voice control technology with a mouse-less browsing plug-in to her browser. The plug-in overlays each hyperlink in rendered content with a number that can then be used to directly select it by speaking a command (e.g. "select link 12"). This prevents Mary from having to say the word 'tab' numerous times to get to her desired hyperlink.
- Related Resources for Success Criterion 2.3.2:
2.3.x Discover navigation and activation keystrokes (former 2.5.1):
The user can discover direct navigation and activation keystrokes both
programmatically and via perceivable labels. (Level A)
- Intent of Success Criterion 2.3.x :
- Examples of Success Criterion 2.3.x :
- Related Resources for Success Criterion 2.3.x :
2.3.3 Direct activation (former 2.7.6):
The user can move directly to and activate any operable
elements in rendered content. (Level AA)
- Intent of Success Criterion 2.3.3 :
It is often difficult for some people to use a pointing device (the standard method of direct navigation) to move the viewport and focus to important elements. In this case some other form of direct navigation - such as numbers or key combinations assigned to important elements - should be available which can then be accessed via the keyboard or speech control technology.
- Examples of Success Criterion 2.3.3 :
- Mary cannot use the mouse or keyboard due to a repetitive strain injury, instead she uses voice control technology with uses a mouse-less browsing plug-in to her browser. The plug-in overlays each hyperlink with a number that can then be used to directly select it (e.g. by speaking the command "select link twelve"). This prevents Mary from having to say the word 'tab' numerous times to get to her desired hyperlink.
- Related Resources for Success Criterion 2.3.3:
- 2.7.7 configure set of important elements @@ Editor's Note - is this still the right number?@@
2.3.4 Present Direct Commands in User Interface (former 2.1.7):
The user can have any direct commands (e.g. keyboard shortcuts) in the user agent user interface be presented with their associated user interface controls (e.g. "Ctrl+S" displayed on the "Save" menu item and toolbar button). (Level AA)
- Intent of Success Criterion 2.3.4:
For many users, including those who use the keyboard or and input method such as speech, the keyboard is often a primary method of user agent control. It is important that direct keyboard commands assigned to user agent functionality be discoverable as the user is exploring the user agent.
- Examples of Success Criterion 2.3.4:
- Vlad is a keyboard-only user who uses a browser on the Mac OS operating system. When he needs to perform a new operation with the browser user interface, he searches for it in the menus and notes whether the menu item has a " ⌘ " label (e.g. "Copy ⌘-C"), which indicates the direct activation command he can use in the future to avoid having to traverse the menus.
- Amir uses ability switches to control an onscreen keyboard for the Windows operating system. When he presses the "alt" key the available browser user interface accesskeys are shown as overlays on the appropriate user interface controls (e.g. "File with 'F' in an overlay").
- Related Resources for Success Criterion 2.3.4:
2.3.5
Customize Keyboard Commands:
The user can override any keyboard shortcut including recognized author supplied shortcuts (e.g. accesskeys) and user interface controls, except for conventional bindings for the operating environment (e.g. arrow keys for navigating within menus). The user must be able to save these settings beyond the current session. (Level AA)
- Intent of Success Criterion 2.3.5
Content authors may utilize the Accesskey attribute to define short cut keys which allow quick access to specific elements, actions, or parts of their Web content. The author-selected short cuts may utilize keystrokes that are unique to their site, differing from conventions used, and or familiar, to users of other similar sites, or sites offering similar functionality. Users of assistive technologies who rely upon keyboard input may wish to have a consistent mapping of shortcut keys to similar, or common actions or functions across the sites they visit.
User agents should allow users to define a preferred key combination for specific instances of author defined accesskeys. The user should have the option to make any defined override to be persistent across browsing sessions.
User agents may also offer the user the option to automatically apply preferred key combinations for content which has author supplied accesskey bindings, based upon the associated text, label, or ARIA role, and which override any author specified keybinding for that page content.
- Examples of Success Criterion 2.3.5:
- A speech recognition user has defined standard commands to access commonly used parts of a Web site. For example, speaking the command "site search" will take the user to a Web site's search function. A site author may assign an access key to set focus to the search input field, basing the accesskey on the first letter of the search engine used (e.g. G for Google or B for Bing, rather than the mnemonic S for search). The speech user has specified an override key mapping of S, which is consistent with the keystroke issued by the speech recognizer they are using.
- A mobile device user, whose primary keyboard interface is their phone's numeric keypad, maps common Web site actions to numeric shortcut keys. For example, the user prefers to have the 1 key to activate a site's "skip to content" function. An author of a site visited daily by this user defines "S" as the accesskey for the skip to content function. The user overrides the author defined accesskey of "S" with "1".
- @@ Editors' Note: good place to add i18n example, accesskey - o umlaut, but not on local keyboard@@
- Related Resources for Success Criterion 2.3.5:
Summary: Users can search rendered content (2.4.1) forward or backward (2.4.2) and can have the matched content highlighted in the viewport (2.4.3). The user is notified if there is no match (2.4.4). Users can also search by case and for text alternatives (2.4.5).
2.4.1 Find:
The user can perform a search within rendered content (e.g. not hidden with a style), including rendered text alternatives and rendered generated content, for any sequence of printing characters from the document character set. (Level A)
- Intent of Success Criterion 2.4.1 :
To provide a function that allows the user to easily locate desired information in rendered or alternative text. Give the option of searching the alternative content. In the case of an embedded user agent, (e.g. media player), the embedded user agent provides the search for its content. @@ Editors' Note: Is this even necessary? Who does the search in an embedded video player?"@@
- Examples of Success Criterion 2.4.1 :
- A user wants to locate a text string in a long document. The user agent provides a mechanism for entering the desired text string, such as a text box with a search button.
- A user wants to search for text in all views of the document, including views of the text source (source view)
- A user wants to search the element content of form elements (where applicable) and any label text.
- @@ Editors' Note: searching video captions??@@
- @@ Editors' Note: Searching embedded SVG?@@
- Related Resources for Success Criterion 2.4.1 :
2.4.2 Find Direction:
The user can search forward or backward in rendered content. (Level A)
- Intent of Success Criterion 2.4.2 :
Searching in any direction from the current point of focus allows for maximum flexibility in allowing the user to easily locate the text used in the search. Users for who reading is difficult can greatly reduce the amount of reading required to find the information needed. Searching improves navigation efficiency which is especially important for people with dexterity issues where every keystroke can be time consuming, tiring or painful. It is recommended that the user also has the ability to search forward or backward within any selected content. @@ Editors' Note: needs some explanation. how to keep searching within the selected content
- Examples of Success Criterion 2.4.2 :
- A user has been reading through a web page and wants to quickly locate a phrase previously read. When opening the browser's page search feature, the user has options to search forward and backward from the current location. If the search reaches an endpoint in the document, the user is notified that the search has wrapped around, such as with an alert box or other indication.
- Related Resources for Success Criterion 2.4.2 :
2.4.3 Match Found:
When a search operation produces a match, the matched content is highlighted, the viewport is scrolled if necessary so that the matched content is within its visible area, and the user can search from the location of the match.
(Level A)
- Intent of Success Criterion 2.4.3 :
It is important for the user to easily recognize where a search will start from.
@@ Editors' Note: If the caret has been moved, from its new location.@@
- Examples of Success Criterion 2.4.3 :
- Example: Jules is low vision and uses a
magnified screen. She frequently searches for terms that appear
multiple times in a document that contains a lot of repetition. It
is important that the viewport moves and if necessary her screen
scrolls after each search so she can easily track where she is in
the document.
- Related Resources for Success Criterion 2.4.3 :
2.4.4 Alert on Wrap or No Match:
The user can be notified when there is no match to a search operation. The user can be notified when the search continues from the beginning or end of content. (Level A)
- Intent of Success Criterion 2.4.4 :
It is important for users to get clear, timely feedback so they don't waste time waiting or, worse, issue a command based on a wrong assumption. It is important during a search that users are informed when there is no match or that the search has reached the beginning of the document.
- Examples of Success Criterion 2.4.4 :
- Dennis uses a screen reader. As soon as he gets a message that
there is no match he goes on to search for something else. If he
does not get a message he wastes time retrying the search to make
sure the entire document has been searched.
- Related Resources for Success Criterion 2.4.4 :
2.4.5 Advanced Find:
The user can search with a case-sensitivity option and the ability to search all content (including alternative content, hidden content, and captions) for any sequence of characters from the document character set. (Level AA)
- Intent of Success Criterion 2.4.5 :
Searching is much more useful when the user can specify
whether case matters in a search and when the user can search
alternative text.
- Examples of Success Criterion 2.4.5 :
- Dennis uses a screen reader. He wants to find all the
instances of his friend Bill in a blog post about finances. He needs
to specify case in order to avoid stopping at instances of "bill".
Later, he searches for his friend's name in a blog post about poetry
where the author never uses capital letters. In this instance he
specifies that case does not matter.
-
Dennis he remembers a portion of a caption for something he
had seen before that he wants to find. He needs to be able to search
on the caption.
- Related Resources for Success Criterion 2.4.5 :
Summary: Users can view (2.5.3), navigate (2.5.5) and configure (2.5.7) content hierarchy.
2.5.3 Location in
Hierarchy:
The user can view the path of nodes leading
from the root of any content hierarchy in which the structure and
semantics are implied by presentation, as opposed to an explicit logical
structure with defined semantics (such as the HTML5 Canvas Element), or
as a consequence of decentralized-extensibility (such as the HTML5 item
/ itemprop microdata elements), and only if the user agent keeps an
internal model of the hierarchy that it does not expose via the DOM or
some other accessibility mechanism. (Level A) .
- Intent of Success Criterion 2.5.3 :
Knowing where you are in a hierarchy makes it easier to understand and
navigate information. Users who are perceiving the data linearly (such
as audio speech synthesis) do not receive visual cues of the
hierarchical information. Efficient navigation of hierarchical
information reduces keystrokes for people for whom keypress is
time-consuming, tiring, or painful. For people with some cognitive
disabilities, providing the clear hierarchy reduces cognitive effort and
provides organization.
- Examples of Success Criterion 2.5.3 :
- A media player provides a hierarchical display of playlists, albums,
artists and songs, etc. When the user selects an individual item, a
breadcrumb of the categories is displayed, can be navigated and is
available programmatically.
- Related Resources for Success Criterion 2.5.3 :
2.5.5 Access to Relationships which Aid Navigation:
The user can access explicitly-defined relationships based on the user's position in content, and the path of nodes leading from the root of any content hierarchy to that position. (Level AA)
- Intent of Success Criterion 2.5.5 :
Let the user use the keyboard to navigate forwards and backwards through elements that they are likely to be interested in interacting with. These elements must include, but are not limited to, enabled links and controls. This allows the user to jump between elements without having to navigate through intervening content such as blocks of text. Efficient keyboard navigation is especially important for people who cannot easily use a mouse.
- Efficient keyboard navigation aids structured navigation by enhancing a users comprehension of their position (e.g. show form control's label, show label's form control, show a cell's table headers, etc.).
- Examples of Success Criterion 2.5.5 :
- The user can press the Tab key to move the focus to the next link or control in the page, or press Shift+Tab to move in the reverse order.
- Related Resources for Success Criterion 2.5.5 :
- See 2.1.4 for discussion of letting the user configure the list of important elements to suit their task.
2.5.7 Configure Elements for Structural Navigation:
The user can configure the sets of important elements (including element types) for structured navigation and hierarchical/outline view. (Level AAA)
- Intent of Success Criterion 2.5.7 :
Often the user agent will choose by default the elements it considers important for structured navigation, however these may not be relevant in all circumstances. It may be that the user wishes to navigate via informal mechanisms such as microformats, decentralised extended elements, or via a particular styling which is used to convey a structure in the visual navigation, but which does not exist in the element hierarchy.
- Examples of Success Criterion 2.5.7 :
- Fred is blind and wishes to navigate through the menu structure using the Tab key, however the menu is a set of nested list elements with a particular HTML class attribute denoting the menu-submenu relationship. Because Fred's user agent allows him to configure important elements he can explicitly include the class name as an important element for navigation. He then assigns a keyboard shortcut to navigate to the next element with the same class name as the element that has the focus.
- Jane's browser allows her to configure important elements and so she can pick out the classes associated with these DIV element, and therefore use the cursor key to move logically through columns or rows.
- Related Resources for Success Criterion 2.5.7 :
Summary:Users can interact with web content by mouse, keyboard, voice input, gesture, or a combination of input methods. Users can discover what event handlers (e.g. onmouseover) are available at the element (2.6.1) and activate an element's events individually (2.6.2) or [@@ Editor's Note: PLACEHOLDER @@] (2.6.3)
2.6.1
List event handlers:
The user can call up a list of input device event handlers explicitly associated with the keyboard focus element, and activate any one or more of the event handlers. (Level A)
- Intent of Success Criterion 2.6.1
:
Users interacting with a web browser may be doing so by using one or more input technologies including keyboard, mouse, speech, touch, and gesture. No matter how the user is controlling the user agent, the user needs to know all the input methods assigned to a particular piece of content. At the same time, anyone input method should not arbitrarily hold back another. For instance, people who don't use a mouse shouldn't necessarily have to map their input methods to the same steps a mouse user would take.
- Examples of Success Criterion 2.6.1
:
- Jeremy cannot use a mouse. He needs to activate a flyout menu that normally appears OnMouseOver. Jeremy can navigate to a link on this flyout menu and activate it using keyboard shortcuts.
- Ken is a speech input user. In order to get his work done in a reasonable amount of time and without overtaxing his voice he uses a single speech command phrase to move the mouse up, left and click.
- Karen cannot use a mouse. She clicks a single key to activate both events for link that has an onmousedown and an onmouseup event link.
- Related Resources for Success Criterion 2.6.1:
Guideline
2.7 - Configure and store preference settings.
Summary: Users can restore preference settings to default (2.7.3), and accessibility settings persist between sessions (2.7.2). Users can manage multiple sets of preference settings (2.7.4), and adjust preference setting outside the user interface so the current user interface does not prevent access (2.7.6). It's also recommended that groups of settings can be transported to compatible systems, and a wizard be available to help users configure their preferences (2.7.7, 2.7.8).
2.7.2
Persistent Accessibility Settings:
User agent accessibility preference settings persist between sessions. (Level A)
- Intent of Success Criterion 2.7.2
:
When a user has customized settings within the user agent to maximize accessibility, this success criteria ensures that customization is saved between browsing sessions. The user can then have those settings automatically used in subsequent browsing sessions.
- Examples of Success Criterion 2.7.2
:
- Lynn has moderately low vision, and sets the default zoom level, font size, and colors to make pages easier for her to read. Because those settings are persistent, she doesn't have to manually restore her settings every time she starts the browser.
- Brian has to adjust some settings in his browser to make it fully compatible with his speech input system. It's difficult for him to get it set up, since he can't fully operate the browser until it's done, so once it's configured this way he relies on it staying in that configuration even if he upgrades the browser, restarts his system and so forth.
- Related Resources for Success Criterion 2.7.2
:
2.7.3
Restore all to default:
The user can restore all preference settings to default values. (Level A)
- Intent of Success Criterion 2.7.3
:
For some users, it may be difficult to easily recall all modified settings while others may find it difficult to navigate to each modified setting, especially if a particular setting may have impacted their ability to do so. Users who customize settings may find that their chosen settings are not suitable and decide to restore these settings to their default values. This success criteria provides a means for a user to easily restore all preference settings to their default values using a single function or action.
- Examples of Success Criterion 2.7.3
:
- Ron accidentally changes a browser setting that makes his browser incompatible with his screen reader, preventing him from changing it back. He instead restarts his browser using a command line option that starts it in the default configuration, which he's able to use, and from there he can change the setting that caused him problems.
- Related Resources for Success Criterion 2.7.3
:
2.7.4
Multiple Sets of Preference Settings:
The
user can save and retrieve multiple sets of user agent preference settings.
(Level AA)
- Intent of Success Criterion 2.7.4
:
Some users may need to change their setting preferences under different circumstances such as varying levels of user fatigue or changes in environmental noise or lighting conditions. Providing an easy method for saving and switching between a set of preferences helps the user complete intended tasks in different situations.
- Examples of Success Criterion 2.7.4
:
- When Hiroki is carrying his tablet computer he operates it with the built-in touchscreen, but when at his desk he links it to a Bluetooth keyboard and mouse, and redirects the display to a full-size computer monitor. The browser allows him to quickly switch between two completely different configurations for these different environments.
- Davy has moderately low vision and prefers to adjust the contrast of media differently during the day than at night. Because this requires a number of different steps, for different types of media and aspects of the browser's display, he has two user profiles, one for each environment.
- Aaron usually uses a keyboard and mouse, but when his repetitive strain injury is bothering him he prefers to use the mouse and avoid using the keyboard as much as possible. At those times he users his browser's user preference profiles to load a different configuration that’s optimized for the mouse, including custom toolbars that make most of the commands he uses available as toolbar buttons.
- Related Resources for Success Criterion 2.7.4
:
2.7.6
Change preference setting outside the user interface:
The user can adjust preference settings from outside the user agent user interface. (Level AA)
- Intent of Success Criterion 2.7.6
:
The user should have the ability to set user preferences to enable accessibility features of a UA prior to launching the UA. When the user inadvertently selects a setting that renders the user interface inaccessible, a method must be provided to allow the user to reset the user interface preferences.
- Examples of Success Criterion 2.7.6
:
- On a desktop device, the settings of the platform are automatically picked up by the user agent, so when the user agent starts, the user is able to use the product. High Contrast.
- On a desktop device, the user can edit the .ini file
- On a mobile a hard button could be used to reset the accessibility parameters on user command.
- Related Resources for Success Criterion 2.7.6
:
2.7.7
Portable Preference Settings:
The user can transfer preference settings across locations onto a compatible system. (Level AAA)
- Intent of Success Criterion 2.7.7
:
A user who has spent time customizing accessibility preferences to meet their needs, can easily migrate preference setting to another device in order to maintain accessibility of other user agents
- Examples of Success Criterion 2.7.7
:
- Rehabilitation specilist sets the email application accessibility preferences on a mobile device. These preferences are reflected in the desktop version of that email application.
- Related Resources for Success Criterion 2.7.7
:
2.7.8
Preferences Wizard:
One or more
wizards help the user to configure the accessibility-related
user agent preferences. (Level AAA)
- Intent of Success Criterion 2.7.8
:
Users who rely on accessibility settings do so for multiple reasons and may want to adjust software settings in many differing fashions. It is key to allow software settings that impact accessibility to be configured to meet these differing needs. The easier such settings are to discover, the more rapidly the user looking for such settings can tailor the software to suit his or her needs. Saving such configuration changes between browsing sessions allows the software to work the way the user wants each time the application is used.
- Examples of Success Criterion 2.7.8
- A user who relies on larger text sizes when browsing web pages, locates a text adjustment setting in a browser's menus. The user sets the text size to the size that makes web content readable. .
- A user locates a control in a web browser called options. Activating this control leads to a series of tabs for adjusting multiple browser settings. One tab is listed as accessibility and has settings such as text size, use custom style sheet, display alternative text in place of images, enable caret browsing and other settings determined to be of benefit to users with disabilities.
- A user is exploring settings for a web browser and locates an option called accessibility. The user is then guided through a series of questions asking about how he or she prefers to use software. Questions such as color preference, text size, ability to view images, the need for captions on videos and such are asked. When the user completes these questions, appropriate browser options are configured and stored.
- A user who has configured accessibility settings in a browser needs to use that application in the same browser on another computer. The browser allows the user to transfer such settings from one computer to another, saving the need to reconfigure the second machine.
- @@ Editors' Note: add another example of persistence@@
- Related Resources for Success Criterion 2.7.8
- SCORM Editors' Note: (Jutta's work) - find current reference @@
Summary: It's recommended that users can add, remove and configure the position of graphical user agent controls (2.8.1) and restore them to their default settings (2.8.2).
2.8.1 Configure Position:
The user can add, remove, and reorder any toolbars and similar containers, and the items within them. (Level AA)
- Intent of Success Criterion 2.8.1 :
This success criterion is about giving the user control over which user interface elements are visible and usable, where they are visually located on the screen, and where they fall in the navigation order. In some cases adjusting whether an element is visible and usable may involve installing/uninstalling a component, or merely showing/hiding it, depending on the user agent and the specific component.
This can reduce keystrokes, bring buttons into view that are hidden by default or otherwise allow the user to interact with the user agent in a more efficient fashion. Users with dexterity impairments or mobility impairments may have problems making the large movements required to select between non-adjacent controls which they need to use frequently. Similarly users with low vision may have to excessively move their magnified view-port to see frequently used controls. Enabling these controls to be situated together removes much of the strain faced by these users, and increases productivity as task completion times are decreased.
- Examples of Success Criterion 2.8.1 :
- Martin accesses the computer by pressing keys with a stick held in his mouth known as a mouthstick and gets around the user agent with taps on the tab and arrow keys. The designers of a user agent have decided to place a button for printing a web page as the last button on a toolbar. This button requires six presses of a right arrow key to reach for Carl and is the only button he uses on the toolbar. Using a preferences dialog, Martin is able to configure this toolbar to only show the Print button, reducing the number of presses he must issue with his mouthstick to one.
- Related Resources for Success Criterion 2.8.1 :
2.8.2 Restore Default Toolbars:
The
user can restore the default toolbar, panel, or inspector configuration. (Level AAA)
- Intent of Success Criterion 2.8.2 :
Mistakes happen. If a user has modified the toolbar incorrectly it can often be difficult to return to a stable state so that these errors can be corrected. There are additional pressures in this regard for people with learning difficulties who make more use of toolbars than they do of textual menus. Building an easily selectable mechanism to restore these defaults saves user time and reduces stress.
- Examples of Success Criterion 2.8.2 :
- Jack is an 80 year old web surfer who is intellectually very sharp but experiences tremors in his hands when required to make fine movements with the mouse. To help himself he is setting up the toolbar so that 'spacers' are placed between each component to prevent accidental selection of adjacent buttons. Today his tremors are particularly bad and Jack makes a number of mistakes becoming increasingly frustrated that while trying to correct these errors he begins to make many more. Jack just wants to start over. Luckily the browser manufacturer has included an easy mechanism to restore the default toolbar configuration. Jack chooses this option and successfully starts over the next day.
- Related Resources for Success Criterion 2.8.2 :
Summary: Users can extend the time limit for user input when such limits are controllable by the user agent (2.9.1); by default, the user agent shows the progress of content in the process of downloading (2.9.2).
2.9.1
Adjustable Timing:
Where time limits for user input are recognized
and controllable by the user agent, the user can extend the time
limits. (Level A)
- Intent of Success Criterion 2.9.1
:
Users of assistive technology, such as screen readers, and those who may require more time to read or understand and act upon content (e.g. individuals with reading disabilities or non-native readers of the presented language) should be able to extend or override any content/author imposed presentation / interaction time limits.
- Examples of Success Criterion 2.9.1
:
- News Alerts: A news organizations Web site has a region of the home page which presents featured stories, cycled every 3 seconds. A user with low vision, using a screen magnifier, requires more than three seconds to read the news item and select it. The user agent provides the user with a global option to freeze all timed events using a keyboard command. Another keyboard command resumes the timed presentation.
- Session Inactivity Timeouts: A screen reader user is logged into a financial services Web site and is reading the site's detailed privacy policy. Because of security policy, the site will terminate the session of any user who has been inactive for 5 minutes. A prompt will appear warning of the impending log off without further action. This user is able to select an option in her non-visual user agent that automatically responds to those prompts if the user agent is currently reading the content.
- Related Resources for Success Criterion 2.9.1
:
2.9.2 Retrieval Progress:
By default, the user agent shows the progress of content retrieval. (Level A)
- Intent of Success Criterion 2.9.2 :
Users need to know that their actions are producing results even if
there is a time delay. Users who cannot see visual indications need to
have feedback indicating a time delay and have an idea of where they are
in the retrieval process. This reduces errors and unnecessary duplicate
actions.
- Examples of Success Criterion 2.9.2 :
- The user has clicked on a link that is downloading a large file. The
user agent displays a programmatically available progress bar. If the
progress stops, the user agent displays a message that it has timed out.
- The user has entered data in a form and is waiting for a response from
the server. If the response hasn't been received in 5 seconds, the user
agent displays a programmatically available message that it is waiting
for a response. If the process times out, the user agent displays a
message that it has timed out.
- Related Resources for Success Criterion 2.9.2 :
- 4.1.6 Expose Accessible Properties
Implementing Guideline 2.10 (former 2.4) - Help users avoid flashing that could cause seizures.
[Return to Guideline]
Summary: To help users avoid seizures, the default configuration prevents the browser user interface and rendered content from flashing more than three times a second above a luminescence or color threshold (2.10.1), or does not flash at all (2.10.2).
2.10.1
Three Flashes or Below Threshold:
In its default configuration, the user agent does not display any user interface components or recognized content that flashes more than three times in any one-second period, unless the flash is below the general flash and red flash thresholds. (Level A)
- Intent of Success Criterion 2.10.1
:
The intent of this Success Criterion is to guard against inducing seizures due to photosensitivity, which can occur when there is a rapid series of general flashing, or red flash. A potentially harmful flash occurs when there is a pair of significantly opposing changes in luminance, or irrespective of luminance, a transition to or from a saturated red occurs.
- Examples of Success Criterion 2.10.1
:
- A single, double, or triple flash -- as long as it does not include changes to or from a saturated red -- may be used to attract a user's attention, or as part of an interface animation.
- An error condition is indicated by flashing that continues until acknowledged by the user. In order to avoid triggering seizures, the flashing is limited to fewer than three times per second, and, to be extra cautious, it is not red.
- Related Resources for Success Criterion 2.10.1
:
2.10.2
Three Flashes:
In its default configuration, the user agent does not display any user interface components or recognized content that flashes more than three times in any one-second period (regardless of whether not the flash is below the general flash and red flash thresholds). (Level AAA) [WCAG 2.0]
- Intent of Success Criterion 2.10.2
:
- The intent of this Success Criterion is to guard against inducing seizures due to photosensitivity, which can occur when there is a rapid series of general flashing, or red flash. A potentially harmful flash occurs when there is a pair of significantly opposing changes in luminance, or irrespective of luminance, a transition to or from a saturated red occurs. 2.10.2 has the same effect as 2.10.1, only goes further to ensure that more sensitive users can traverse the Web without potentially harmful effects.
- Examples of Success Criterion 2.10.2
:
- Related Resources for Success Criterion 2.10.2
:
- refer to 2.11.2 and 2.11.6
Summary: The user can control background images (2.11.1); present placeholders for time-based media (2.11.2) and executable regions (2.11.3), or block all executable content (2.11.4); adjust playback (2.11.5), stop/pause/resume (2.11.6), navigate, (2.11.7) and specify tracks for prerecorded time-based media (2.11.9); scale and position alternative media tracks (2.11.11); and adjust contrast and brightness of visual time-based media (2.11.12).
2.11.1 Background Image
Toggle:
The user has the global option to hide or show background images. (Level A)
- Intent of Success Criterion 2.11.1 :
Users can have difficulty reading text or recognizing images that are shown against variable backgrounds. Background images can also be distracting, especially to some people with cognitive impairments.
- Examples of Success Criterion 2.11.1 :
- John finds multiple images behind the text he is reading distracting. He navigates to his favorite news site where he finds today's weather displayed over a picture of a sunny sky with fluffy clouds. He activates a button on a toolbar named "Hide Background" and now can easily determine he's in for a day filled with sunshine.
- Sasha requires high contrast to be able to discriminate the shape of letters. She always sets a preference in her browser to turn off background images, so that she can see the text clearly without the variations in the background.
- Related Resources for Success Criterion 2.11.1 :
- 1.1.1 Configure Default Rendering allows the user to hide foreground images by replacing them with alternative content, but 2.11.1 extends this to background images in languages such as HTML that do not support alternative content for background images.
2.11.2 Time-Based Media
Load-Only:
The user can have placeholders rendered for time-based media content, such that the content is not played until explicit user request. (Level A)
- Intent of Success Criterion 2.11.2 :
- Examples of Success Criterion 2.11.2:
- Jill browses browses the web using a screen reader to listen to the text of web pages. She navigates to her favorite shopping site and is greeted with trumpets blaring and an announcer shouting "Sale, sale, sale!" The audio is so loud that she can no longer hear the web page content. Jill closes her browser and changes a setting titled Play Audio on Request to yes and visits her shopping site again. This time she can read the content and when she is ready plays the audio and smiles, thinking of the deal's she is about to find.
- Jamie has epilepsy that's triggered by certain types of audio. She sets browser so that content does not play automatically so she can avoid audio that could trigger her epilepsy.
- Kendra has photo-epilepsy. She sets her browser so that content does not play automatically so she can avoid flashing content that could trigger her photo epilepsy.
- Related Resources for Success Criterion 2.11.2:
- Guideline 2.10 Help users avoid flashing that could cause seizures.
2.11.3 Execution
Placeholder:
The user can
render a placeholder instead of executable
content that would normally be contained within an on-screen area (e.g.
Applet, Flash), until explicit user request to
execute. (Level A)
- Intent of Success Criterion 2.11.3
:
Documents that do things automatically when loaded can delay, distract, or interfere with user's ability to continue with a task. In the case of embedded objects, applets and media, replacing the executable content with a placeholder tells the user what has been blocked and provides a mechanism (e.g. a play button) for unblocking when the user is ready.
- Note: It is generally recommended that the placeholder take up the same space as the object it is replacing, so that the presentation does not need to be reflowed when the execution is started. However, users on mobile devices or using screen enlargers, or who have difficulty with scroll commands may benefit from having the option of a smaller placholder.
- Examples of Success Criterion 2.11.3
:
- Jane has difficulty concentrating. In order to concentrate on the text of a document she wants to hide any multimedia content, and only trigger execution of that content by clicking on the placeholder she feels it's appropriate.
- Evan is blind. He sets the option in his browser so that when a web page loads it does not automatically run an executable object, so that any or music or speech they play won't interfere with his ability to hear his screen reader. When he is ready to start it playing he navigates to the placeholder and presses the Enter key to activate it.
- Related Resources for Success Criterion 2.11.3
:
2.11.4 Execution Toggle:
The
user can turn on/off the execution
of executable content that would not normally be contained within a
particular area (e.g. Javascript). (Level A)
- Intent of Success Criterion 2.11.4
:
Documents that do things automatically when loaded can delay, distract, or interfere with user's ability to continue with a task. The user needs to be able to specify that executable content (e.g. scripts) be blocked when a document loads, be told which content has been blocked, and be able to selectively execute the content at a later time.
- Note: Some web applications and document may be essentially empty until scripts are run. However, it is still important for users to have this level of control.
- Examples of Success Criterion 2.11.4
:
- Jane has difficulty concentrating. In order to concentrate on the text of a document she wants to prevent any animations, media, or dynamic content from executing until she is ready. An icon on the status bar tells her that scripts have been blocked, and by clicking it she can select which scripts to run.
- Evan is blind. He sets the option in his browser so that when a web page loads it does not automatically start running scripts that might play sounds that would interfere with his ability to hear his screen reader. An icon on the status bar tells him that scripts have been blocked, and by activating it he can select which scripts to run.
- Related Resources for Success Criterion 2.11.4
:
2.11.5 Playback Rate Adjustment for Prerecorded Content:
The user can adjust the playback rate of prerecorded time-based media content, such that all of the following are true: (Level A)
- The user can adjust the playback rate of the time-based media tracks to between 50% and 250% of real time.
- Speech whose playback rate has been adjusted by the user maintains pitch in order to limit degradation of the speech quality.
- Audio and video tracks remain synchronized across this required range of playback rates.
- The user agent provides a function that resets the playback rate to normal (100%).
- Intent of Success Criterion 2.11.5:
Users with sensory and cognitive impairments may have difficulty following or understanding spoken audio when presented at the normal playback rate. By slowing down the audio presentation of speech, while maintaining the pitch, or frequency characteristics, users are better able to follow the spoken content. For users with visual impairments familiar with the speeding up of speech presentation using screen readers or digital audio book players, the ability to speed up the audio, while maintaining pitch, allows those users to skim spoken audio without loss of understandability of the speech. Users with learning disabilities may be distracted or otherwise unable to follow complex animations or instructional video. By allowing the presentation to be slowed, the user has a better opportunity to observe the visual events of the animation. Additionally, a person may want to slow down the media if they are trying to take notes, and do so slowly because of language or dexterity impairments, etc.
- Examples of Success Criterion 2.11.5:
- Timo experienced a traumatic brain injury and has difficulty in comprehending speech. When listening to episodes of his favorite podcast on the Web, he slows down the audio by 50% and is able to understand the interviewer's and guest's question and answer session.
- Anu is a blind university student who has grown up with digital talking book players, and regularly listens to spoken audio at 200% of normal speaking rate. In studying for exams, she reviews the online lecture videos from her History course, adjusting the presentation rate to 2x on the Web video player, in order to quickly review the material, and slowing the presentation down to normal rate when she encounters material she needs to review carefully.
- Perttu has a learning disability and requires a longer time to follow instructions. He likes to cook and is watching a cooking demonstration on the Web. The instructions go by too quickly, and Perttu slows the video player to half speed in order to make it easier to follow the recipe being prepared.
- Related Resources for Success Criterion 2.11.5:
2.11.6 Stop/Pause/Resume
Time-Based Media:
The user can stop, pause, and resume rendered audio and
animation content (including video,
animated images, and changing text) that last three or more seconds at their default playback
rate. (Level A)
- Intent of Success Criterion 2.11.6:
Users with sensory, attentional, or cognitive impairments may have difficulty following or understanding multimedia content. By allowing time-based media to be stopped, paused, and resumed, users are able control the presentation rate, providing time to understand or act upon presented content before continuing, or to stop potentially distracting or harmful content.
- Examples of Success Criterion 2.11.6:
- Adam reads more slowly than average because of his dyslexia. He's watching a video of a lecture, and when the video shows slides, he presses the space bar to pause the video so that he can read the text at his own speed. When he's ready to continue, he presses the space bar again to resume the video.
- Angelica uses a web site to watch and listen to user-contributed podcasts, but when one starts playing she realizes that the level of white noise in the soundtrack is likely to trigger her audio-induced seizures. She quickly clicks on the player's STOP button (or presses the equivalent keyboard command) and the noise is instantly discontinued.
- Allesandro finds it impossible to ignore visual changes, and so finds unnecessary animations make it very difficult for him to read or interact with other content on the screen. When he's trying to read an article on a newspaper's web site and finds an animated advertisement or moving text of a news ticker continually distracting him, he presses the Esc key (or chooses the appropriate command from the menu bar) to tell his web browser to stop all animations.
- Amaryllis is blind and is listening to streaming audio on a web page. When she wants to respond to an incoming email message she needs to pause the audio, which would otherwise interfere with her ability to hear her screen reader.
- Related Resources for Success Criterion 2.11.6:
2.11.7 Navigate Time-Based Media:
The user can navigate along the timebase using a continuous scale, and by relative time units within rendered audio and animations (including video and animated images) that last three or more seconds at their default playback rate. (Level A)
- Intent of Success Criterion 2.11.7 :
Users with sensory, cognitive or attentional impairments may find it difficult to understand or follow time-based media. This success criteria allows users to position within the timebase to review content or to skip content which may be distracting.
- Examples of Success Criterion 2.11.7 :
- Jared has a print disability which makes it laborious to read text. He is watching a technical training video which will display section objectives or summary questions as text. When the text flashes by too quickly for him to read, he presses a key command to skip back an increment so he can read the text, or pause the video if more time is required.
- Debbie has difficulty with bright or flashing video. When she encounters a flashing transition in a video, she quickly presses a key command to forward the video past the flashing, then carefully uses the slider to adjust the video back to the start of the next section avoiding the flashing material.
- Related Resources for Success Criterion 2.11.7 :
2.11.8 Semantic Navigation of Time-Based Media:
The user can navigate by semantic structure within the time-based media, such as by chapters or scenes present in the media (Level AA).
- Intent of Success Criterion 2.11.8:
Users need to be able to navigate time-based media in ways that are more meaningful than arbitrary time increments.
- Examples of Success Criterion 2.11.8:
- Marka is blind and is listening to a video of an hour-long lecture. The section she is in has some complex material that builds on material from an earlier section. While a sighted user could pause the video and move the slider back until she recognized visually distinct content from the section she wanted, Marka uses a control to skip back section by section until she hears the section title name she wants to review. When she is finished, Marka uses the control to move forward section by section until she hears the title of topic she was originally in.
- Wes has repetitive stress injury that limits the length of his computer sessions. He stops playback of a training video when he is tired and after resting, he can restart it and navigate to the scene where he left off.
- Related Resources for Success Criterion 2.11.8 :
2.11.9 Track Enable/Disable of Time-Based Media:
During time-based media playback, the user can determine which tracks are available and select or deselect tracks, overriding global default settings for captions, audio descriptions, etc. (Level AA)
- Intent of Success Criterion 2.11.9 :
Some users with disabilities need to choose different languages or audio tracks (e.g. descriptive video). Users need the ability to choose the tracks that best meet their accessibility needs (e.g. the caption track in their own language) when authors have provided many alternatives.
- Examples of Success Criterion 2.11.9 :
- Marka is listening to a video of a lecture. The professor is demonstrating a chemistry experiment and is not speaking during a key part. Since she cannot see what the professor is demonstrating, Marka brings up a menu of the available tracks and discovers that there is a audio description track available. Marka selects the description track, rewinds a few minutes, and listens to the description of the experiment.
- Gorges is deaf, enjoys current run movies, and subscribes to a web service that streams major popular movies. While he speaks English, a certain movie uses a slang that he doesn't understand. He pauses the movie, selects a menu of caption tracks and finds a Spanish caption track. He then watches the rest of the movie with Spanish captioning.
- Related Resources for Success Criterion 2.11.9 :
2.11.11 Scale and position visual alternative media tracks:
The user can scale and position alternative media tracks independent of base video. (Level AAA)
- Intent of Success Criterion 2.11.11 :
Text scaling - default setting should apply, UA should allow separate
control of the caption tracks. User needs larger captions. Snap captions outside of video, change text size and caption viewport size/position. User need to reposition and make the sign language track larger.
- Examples of Success Criterion 2.11.11 :
- Justin has low vision and works in a noisy environment that makes it difficult to listen to instructional videos. When he enlarges the text of the captions to a viewable size, they block most of the video image. Justin selects an option that displays the caption track in a separate window, which he positions below the video image so the captions do not block the video image.
- Related Resources for Success Criterion 2.11.11 :
2.11.12 Video Contrast and Brightness:
Users can adjust the contrast and brightness of visual time-based media. (Level AAA)
- Intent of Success Criterion 2.11.12 :
Text scaling - default setting should apply, UA should allow separate
control of the caption tracks. User needs larger captions. Snap captions outside of video, change text size and caption viewport size/position. User need to reposition and make the sign language track larger.
- Examples of Success Criterion 2.11.12 :
- Frank has low vision that requires a higher contrast to discern a video image. When Frank is watching an instructional video, he selects a menu item that allows him to increase the contrast of the video, to make it easier for him to see the important content.
- Kelly has photo-epilepsy and is watching an amateur video taken on a sunny day near the water. Concerned that the video may contain flashing that could trigger a seizure, Kelly selects a menu item of video controls that allow her to reduce the brightness and contrast of the video. While some of the detail is lost, Kelly can safely watch the video.
- Related Resources for Success Criterion 2.11.12 :
Applicability Notes:
Guideline 2.11 and its success criteria only applie to images, animations, video, audio, etc. that
the user agent can recognize.
Summary: For all input devices supported by the platform, the user agents should let the user perform all functions aside from entering text (2.12.2), and enter text with any platform-provided features (2.12.1). If possible, it is also encouraged to let the user enter text even if the platform does not provide such a feature (2.12.3).
2.12.1 Support Platform Text Input Devices:
If the platform supports text input using an input device, the user agent is compatible with this functionality. (Level A)
- Intent of Success Criterion 2.12.1:
Some users rely entirely on pointing devices, or find them much more convenient than keyboards. These users can operate applications much more easily and efficiently if they can carry out most operations with the pointing device. It is not the intention of these guidelines to require every user agent to implement its own on-screen keyboard on systems that do not include them, but on systems where one is included it is vitally important that the user agent support this utility.
- Examples of Success Criterion 2.12.1:
- Ruth has extremely limited motor control and slurred speech, so operates her computer using a head pointer. Her desktop operating system includes a built-in on-screen keyboard utility, and even though the percentage of desktop users who use it is very small, she counts on new applications (including user agents) to be tested and compatible with it so that she can enter text. When active, the on-screen keyboard reserves the bottom portion of the screen for its own use, so the user agent respects this and does not cover that area even in modes that would normally take up the full screen. It also avoids communicating with the keyboard through low-level system API that would miss simulated keyboard input.
- Related Resources for Success Criterion 2.12.1:
2.12.2 Operation With Any Device:
If an input device is supported by the platform, all user agent functionality other than text input can be operated using that device. (Level AA)
- Intent of Success Criterion 2.12.2:
Some users rely entirely on pointing devices, or find them much more convenient than keyboards. These users can operate applications much more easily and efficiently if they can carry out most operations with the pointing device, and only fall back on a physical or on-screen keyboard as infrequently as possible. If the platform provides the ability to enter arbitrary text using a device (such as large vocabulary speech recognition or an on-screen keyboard utility), the user agent is required to support it per 2.12.1 Text Input With Any Device. If the platform does not provide such a feature, the browser is encouraged to provide its own, but because that is generally more difficult and resource intensive than command and control it is not required.
- Examples of Success Criterion 2.12.2:
- Ruth has extremely limited motor control and slurred speech, so operates her computer using a head pointer. The mouse pointer moves in response to the orientation of her head, and she clicks, double clicks, or drags using a sip-and-puff switch. It is much easier for her to point and click on a button or menu item than it is for her to simulate keyboard shortcuts using her on-screen keyboard. In fact, she prefers to customize her applications to make most functions available through toolbar buttons or menu items, even those that are by default available only through keyboard shortcuts.
- Randall has a web browser on his smart phone that allows him to perform most operations using speech commands. Unfortunately, a few features are only available through the touchscreen, which he can only operate by taking off his protective gloves. In the next version of the browser, the remaining features are given keyboard commands, and Randall finds the product safer and more convenient to use.
- Related Resources for Success Criterion 2.12.2:
2.12.3 Text Input With Any Device:
If an input device is supported by the platform, all user agent functionality including text input can be operated using that device. (Level AAA)
- Intent of Success Criterion 2.12.3:
Some users rely entirely on pointing devices, or find them much more convenient than keyboards. These users can operate applications much more easily and efficiently if they can carry out most operations with the pointing device, and only fall back on a physical or on-screen keyboard as infrequently as possible. If the platform provides the ability to enter arbitrary text using a device (such as large vocabulary speech recognition or an on-screen keyboard utility), the user agent is required to support it per 2.12.1 Text Input With Any Device. If the platform does not provide such a feature, the browser is encouraged to provide its own.
- Examples of Success Criterion 2.12.3:
- Ruth has extremely limited motor control and slurred speech, so operates her computer using a head pointer. The mouse pointer moves in response to the orientation of her head, and she clicks, double clicks, or drags using a sip-and-puff switch. The operating system does not provide an on-screen keyboard, but in order to be maximally accessible, a small on-screen keyboard is available as an add-on for her browser.
- Randall has a web browser on his smart phone that allows him to perform most operations using speech commands. By offloading the speech recognition to an Internet server, it is able to perform large vocabulary speech recognition, so Randall can use his voice to compose email and fill in forms, as well as controlling the browser itself.
- Related Resources for Success Criterion 2.12.3:
PRINCIPLE 3: Ensure that the user interface is
understandable
Implementing Guideline 3.1 - Help users avoid
unnecessary messages.
[Return to Guideline]
Summary: Users can turn off non-essential messages from the author or user-agent.
@@ Editors' Note: Add SC based on this note from IRC of 10 November 2010: We could consider adding to this section a recommendation that messages have a checkbox that lets the user avoid getting the message again. But I'm not sure how we could write it to have an appropriate scope, that is only apply to messages where it's appropriate. AND when you do have those check boxes, it's also useful to have something in the application's settings that allows the user to reset those to their default, thus making all the messages visible again.@@
3.1.2 Option to Ignore:
The
user can turn off rendering of
non-essential or low priority text messages or updating/changing information in the content based on priority properties
defined by the author or the user agent. (Level AA)
- Intent of Success Criterion 3.1.2 :
Messages designed to inform the user can be a burden to users for whom
keypress is time-consuming, tiring, or painful. It's important that
these users be able to avoid unnecessary messages.
- Examples of Success Criterion 3.1.2 :
- The browser has an update ready. The user should have the option to be
informed of an update or, instead, only get update information when the
user actively requests it.
- A web page has a stock market ticker display. A user with cognitive disabilities is distracted by the page flicker and wishes to turn off the update. The browser has an menu option to set the level of interruptions, that the user sets to off.
- Related Resources for Success Criterion 3.1.2 :
Summary: Users can choose to confirm form submissions. [@@ Editor's Note: Add SC for built-in spell checking, and back button (navigational undo)@@]
3.2.1 Form Submission:
The user can specify whether or not recognized form submissions must be confirmed. (Level AA)
- Intent of Success Criterion 3.2.1 :
Users need to be protected against accidentally submitting a form. Some
assistive technologies use the Enter key to advance to the next field.
If the form is designed to submit on Enter, the user can unknowingly
submit the form. Those users need to be able to disable the ability to
submit on Enter.
- Examples of Success Criterion 3.2.1 :
- Upon installation of a web browser, a screenreader user selects an
option to disable form submission on Enter. This is a preference option
that can be easily discovered and changed by the user in the future.
This allows the user to complete forms from the banking website knowing
that the submit button must be selected in order to submit the form.
- Related Resources for Success Criterion 3.2.1 :
- @@ Editors' Note: link to section 2.1, especially 2.1.2 and 2.1.10 @@
Summary: User documentation is available in an accessible format (3.3.1), it includes accessibility features (3.3.2), delineates differences between versions (3.3.3), provides a centralized views of conformance UAAG2.0 (3.3.4), and is available as context sensitive help in the UA (3.3.5).
3.3.1 Accessible documentation:
The product documentation is available in a format that meets success criteria of WCAG 2.0 Level "A" or greater. (Level A)
- Intent of Success Criterion 3.3.1 :
User agents will provide documentation in a format that is accessible.
If provided as Web content, it must conform to WCAG 2.0 Level "A" and
if not provided as Web content, it must be in conformance to a
published accessibility benchmark and identified in any conformance
claim for the user agent. This benefits all users who utilize
assistive technology or accessible formats.
- Examples of Success Criterion 3.3.1 :
- A user agent installs user documentation in HTML format conforming to
WCAG 2.0 Level "A". This documentation is viewed within the user agent
and is accessible in accordance with the conformance of the user agent
to UAAG 2.0.
- A user agent provides documentation in HTML format conforming to WCAG
2.0 Level "AA" and is available online. In addition, the user agent
provides user documentation in a locally installed digital talking
book content format in conformance with a recognized, published
format.
- Related Resources for Success Criterion 3.3.1 :
3.3.2 Document Accessibility
Features:
All features of the user agent that meet User Agent Accessibility Guidelines 2.0 success criteria are documented. (Level A)
- Intent of Success Criterion 3.3.2 : [@@ Editor's note: Needs work to adjust to updated SC@@]
User agent documentation that includes listings and descriptions of
features supporting or benefiting accessibility permits users to have
access to a description of accessibility and compatibility features.
This benefits all users with disabilities who may require assistance
in identifying which accessibility features may be present or how to
configure those features to work with assistive technology.
The user should be able to easily discover detailed information about the user agent’s adherence to accessibility standards, including those related to content such as HTML and WAI-ARIA, platform standards such as MSAA or JAA, and third-party standards such as ISO 9241-171, and should be able to do so without installing and testing the accessibility features.
- Examples of Success Criterion 3.3.2 :
- In a section entitled "Browser Features Supporting Accessibility", a
vendor provides a detailed description of user agent features which
provide accessibility, describing how they function, and listing any
supported third party assistive technologies that may be supported or
required.
- A user is exploring the menus of a user agent and finds a feature named Use My Style Sheet. Activating help the user quickly learns that this feature allows custom CSS stylesheets to be created to help make web content more accessible.
- Related Resources for Success Criterion 3.3.2 :
3.3.3 Changes Between
Versions:
Changes to features that meet UAAG 2.0 success criteria since the previous user agent release are documented. (Level AA)
- Intent of Success Criterion 3.3.3 :
As accessibility features are implemented in new versions it is important for users to be able to be informed about these new features and how to operate them. The user should not have to discover which new features were implemented in the new version.
- Examples of Success Criterion 3.3.3 :
- Martha goes to an app store on her computer and notices that an update for the web browser she uses is available. When she installs it she finds a welcome page talking about the new features in this release, and one of the links on that page says "What's New For Accessibility". Following this link Martha reads about the accessibility improvements added and discovers this update had added a feature allowing her to have tooltips displayed for elements when she is using caret browsing. The text also informs Martha that this feature is off by default and that she should go to accessibility settings to turn it on.
- Related Resources for Success Criterion 3.3.3 :
3.3.4 Centralized View:
There is a dedicated section of the documentation that presents a view of all features of the user agent necessary to meet the requirements of User Agent Accessibility Guidelines 2.0. (Level AAA)
- Intent of Success Criterion 3.3.4 :
Specific accessibility features are important for users to know about and how to operate. The user should not have to discover where the accessibility features are documented in context (although that too is very useful). A specific section devoted to only accessibility features (e.g. keyboard shortcuts, how to zoom the viewport, where to find accessibility configuration settings), would make it easier for user to become more functional more quickly with the user agent.
- Examples of Success Criterion 3.3.4 :
- Bob downloads a new web browser on his mobile phone. He's never used this software before and also uses a screen reader that is part of his phone's operating system. The browser's online help includes a section on accessiblity that point him to pages discussing non-visual access, such as interaction with screen readers, as well as helpful hints such as an explanation of the screen layout...
...and a list of supported touch gestures.
- A specific section in the documentation (local or online) detailing accessibility features of the user agent.[@@ Editor's Note: what about accessibility features of plugins, extensions, etc. they are not user agents by them selves. how do user find out about accessibility features if any in the extension?@@]
- Related Resources for Success Criterion 3.3.4 :
Implementing Guideline 3.4 - The user agent must behave in a predictable fashion.
[Return to Guideline]
Summary: Moving the focus allows presentation of information (e.g. tooltips) but does not cause any other action (3.4.2). Users can prevent non-requested focus changes (3.4.1).
3.4.1 Avoid unpredictable focus [formerly 3.4.2, before that 5.4.2, and 1.9.10, broadened] :
The user can prevent focus changes that are not a result of explicit user request. (Level A)
- Intent of Success Criterion 3.4.1 :
Users need to know that navigation in a web page is going to start in a predictable location and move in a predictable fashion. If a page moves the initial focus to somewhere other than the beginning of the page, the user may not realize they have skipped over some content, especially if they can only see a small portion of the page at a time. Similar problems may occur if the content or user agent automatically moves the focus while the user is reading or entering data on a page. If the focus moves without the user recognizing it, they can easily end up entering data in an incorrect field or taking other unintentional actions. Users can also become confused or disoriented when a window scrolls when they haven't requested it. This is particularly problematic for users who can only see a small portion of the document, and thus have to use more effort to determine their new context. Such users also are more likely to continue typing, not immediately realizing that the context has changed. Users for whom navigation is time consuming, tiring, or painful (including those using screen readers or with impaired dexterity) may also need more steps to return to the area where they want to work. While we recognize it may improve accessibility for some users on some pages to have the page to set focus to specific link or field when the page loads, it can also be detrimental for some users, and therefore users needs to be in control of this behavior.
- Examples of Success Criterion 3.4.1 :
- Jerome has loaded a page that sets its default focus to a search box. Because he wants to read the content of the page, rather than starting by entering data, it takes him additional scrolling to get to the content that was not in the search box. To prevent this, he adjusts his browser's settings to disable the automatic focus change on this page.
- Jessica uses a screen enlarger, and loads a page that contains instructions followed by a form. If the page automatically moves the keyboard focus to the form, she may not realize there were instructions. To avoid this problem, she sets an option to prevent default focus changes.
- James uses speech recognition. He speaks his credit card number by saying several digits and, if needed, Tab keys, in a single phrase. He needs to know ahead of time whether it is necessary to include the Tab command in the phrase.
- Joey is filling in a Web form that asks for his phone number using three separate fields. When she types the three digits of her area code into the first field, the browser automatically moves the focus to the second field. This can be a problem for two reasons, first because if Joey is not looking at the screen she does not realize that the focus has moved for her, and so she presses the Tab key to move it manually, not realizing that this now puts the focus on the third field rather than the second. It can also pose a problem if Joey realizes that she typed one digit incorrectly in the area code field, because when she presses Shift+Tab to return and edit that field, the browser or content script checks the number of digits that have been entered, and seeing that it is three, automatically moves the focus once again, preventing her from editing the number. To avoid these problems, Joey goes to her browser's Preferences dialog box and checks the option that prevents focus changes that she has not explicitly requested.
- Justine uses a keyboard macro to execute a multistep command at a specific location. The focus changes without her control, so the command fails or executes with unpredictable results.
- Related Resources for Success Criterion 3.4.1 :
- UAAG 2.0 3.10.8 Don't Move Focus
- 1.8.6 Open on request
- 1.8.7 Do not take focus
3.4.2 Avoid Side Effects of Navigation [former 1.9.1, before that 3.11.11, changed]:
The user can move the keyboard focus without causing the user agent to take any further action, other than the presentation of information (e.g. scrolling or pop-ups that do not change the focus or selection). (Level A)
- Intent of Success Criterion 3.4.2 :
People do not expect side effects when moving the keyboard focus. If users fail to notice side effects, they could end up doing something disastrous, and this is especially likely for users of assistive technology who cannot see changes happening elsewhere on the screen. Users may also find it confusing or disorienting if the effect causes unexpected focus movement or changes in context. If the user agent does implement side effects to keyboard navigation, it is recommended that it provide a user preference setting to disable them. However, in some cases it may be more appropriate to provide a separate navigation mechanism that avoids side effects, such as allowing the user to hold down the Ctrl key while navigating to avoid changing selection or choice.
Note: It may not be possible for the user agent to detect or prevent side effects implemented by scripts in the content, but the user agent is required to prevent side effects that are under its control.
- Examples of Success Criterion 3.4.2 :
- Murray uses a screen enlarger that allows him to see the element with the focus and a small area around it. He explores a dialog box by repeatedly pressing the Tab key to move to, and read, each control in succession, although he has to use the arrow keys to navigate between options in an option group. On this platform moving the focus to an option control automatically chooses that option, making it cumbersome for him because of the need to reset the choice to its original state afterward. Fortunately, the platform also has a convention that holding down the Ctrl key while navigating will move the focus without changing selection or option choice, so Murray uses this while exploring. His Web browser implements its own form controls and navigation mechanisms rather than using the platform's infrastructure, but it also implements this Ctrl-key mechanism for users like Murray.
- Related Resources for Success Criterion 3.4.2 :
@@ Editors' Note: Missing: Greater ease in interpreting security messaging. Should be cross-referenced with the security working group. @@
PRINCIPLE 4: Facilitate programmatic access
Implementing Guideline 4.1 - Facilitate
programmatic access to assistive technology
[Return to Guideline]
Summary: Be compatible with assistive technologies by supporting platform standards (4.1.1), including providing information about all menus, buttons, dialogs, etc. (4.1.2, 4.1.6), access to DOMs (4.1.4), and access to structural relationships and meanings, such as what text or image labels a control or serves as a heading (4.1.5). Where something can't be made accessible, provide an accessible alternative version, such as a standard window in place of a customized window (4.1.3). Make sure that that programmatic exchanges are quick and responsive (4.1.7).
4.1.1 Platform Accessibility Architecture:
The user agent supports a platform accessibility architecture
relevant to the operating environment. (Level A)
- Intent of Success Criterion 4.1.1 :
Computers, including many smart phones, have accessibility features and support for Assistive Technologies built into the operating system. Assistive technologies often use a combination of methods to get information about, and manipulate, a user agent's user interface and the content it's rendering. These methods include DOMs, accessibility APIs such as MSAA or JAA, general-purpose platform APIs such as those used to determine a window's title, application-specific APIs that that are typically a last resort when an application does not make all information available through the former means, and hard-coded heuristics. It is the user agent's responsibility to make the necessary information and facilities available through the appropriate corresponding means. Platform accessibility API is particularly important because it provides common functionality across all (or at least all well behaved) applications running on the platform, reducing the amount of special-casing the assistive technology has to implement for each of the hundreds of applications it supports.
- Examples of Success Criterion 4.1.1 :
- Browser A is developing a new user interface button bar for their Microsoft Windows product. The developer codes a call to the MSAA API for the functionality.
- Related Resources for Success Criterion 4.1.1 :
4.1.2 Name, Role, State, Value,
Description:
For all user interface components including user interface, rendered content, generated content, and alternative content, the user agent makes available the name, role, state, value,
and description via a platform accessibility architecture. (Level A)
- Intent of Success Criterion 4.1.2 :
The information that assistive technology requires is the
- Name (component name)
- Role (purpose, such as alert, button, checkbox, etc)
- State (current status, such as busy, disabled, hidden, etc)
- Value (information associated with the component such as, the data in a text box, the position number of a slider, the date in a calendar widget)
- Description (user instructions about the component).
For every component developed for the user agent, pass this information to the appropriate accessibility platform architecture or application program interface (API). Embedded user agents, like media players can pass Name, Role, State, Value and Description via the WAI-ARIA techniques.
- Examples of Success Criterion 4.1.2 :
- A browser is developing a component to search a listing of files stored in folders. The text box to enter the search terms is coded to pass the following information:
Name
State
STATE_FOCUSABLE
STATE_SELECTABLE
@@ Editors' Note: This needs to be finished and be a legitimate example. Help! @@
- A media player implements a slider to control the sound volume. The developer codes the component to pass the following information to the accessibility API:
Name = Volume control
Role = Slider
States & Values
aria-valuenow
The slider’s current value.
aria-value-min
The minimum of the value range
aria-value-max
The maximum of the value range
Description
aria-describedby = 'Use the right or left arrow key to change the sound volume.'
- Related Resources for Success Criterion 4.1.2 :
- @@ Editors' Note: [more needed]
http://msdn.microsoft.com/en-us/library/ms697187
- http://www.mozilla.org/access/windows/msaa-server
4.1.3 Accessible
Alternative:
If a component of the user agent user interface cannot be exposed through the platform accessibility architecture, then the user agent provides an equivalent alternative that is exposed through the platform accessibility architecture. (Level A)
- Intent of Success Criterion 4.1.3 :
Users who rely on assistive technology need to be able to carry out all tasks provided by the user agent, just like everyone else. When a particular user interface component cannot support for the platform accessibility architecture, and thus can't be made compatible with assistive technology, the user agent should let the user achieve the same goal using another component that IS fully accessible.
- Examples of Success Criterion 4.1.3 :
- The user agent provides a single, complex control for 3-dimensional manipulation of a virtual object. This custom control cannot be represented in the platform accessibility architecture, so the user agent provides the user the option to achieve the same functionality through an alternate user interface, such as a panel with several basic controls that adjust the yar, spin, and roll independently.
- Related Resources for Success Criterion 4.1.3 :
4.1.4 Programmatic Availability of
DOMs:
If the user agent implements one or more DOMs, they must be
made programmatically available to assistive technologies. (Level A)
- Intent of Success Criterion 4.1.4 :
User agents (and other applications) and assistive technologies use a combination of DOMs, accessibility APIs, native platform APIs, and hard-coded heuristics to provide an accessible user interface and accessible content (http://accessibility.linuxfoundation.org/a11yspecs/atspi/adoc/a11y-dom-apis.html). It is the user agents responsibility to expose all relevant content to the platform accessibility api. Alternatively, the user agent must respond to requests for information from APIs.
- Examples of Success Criterion 4.1.4 :
- In user agents today, an author may inject content into a web page using CSS (generated content). This content is written to the screen and the CSS DOM. The user agent does not expose this generated content from the CSS-DOM (as per CSS recommendation) to the platform accessibility API or to the HTML-DOM. This generated content is non-existent to an assistive technology user. The user agent should expose all information from all DOMs to the platform accessibility API.
-
A web page is a compound document containing HTML, MathML, and SVG. Each has a separate DOM. As the user moves through the document, they are moving through multiple DOMs. The transition between DOMs is seamless and transparent to the user and their assistive technology. All of the content is read and all of the interaction is available from the keyboard regardless of the underlying source code or the respective DOM.
- Related Resources for Success Criterion 4.1.4 :
4.1.5 Write Access:
If the user can modify the state or value of a piece of content through the user interface (e.g., by checking a box or editing a text area), the same degree of write access is available programmatically.
(Level A)
- Intent of Success Criterion 4.1.5 :
If the user can affect the user interface using any form of input, the same affect may be done through programmatic access. It is often more reliable for assistive technology to use the programmatic method of access versus attempting to simulate mouse or keyboard input.
- Examples of Success Criterion 4.1.5 :
- When the user says the phrase 'Volume 35%' their speech input utility can programmatically set the value of the volume slider to 35%, rather than having to use trial and error by simulating mouse clicks or arrow presses to try to find the 35% point.
- "Francois directs his third-party macro utility to set the value of a tri-state check box to "mixed". Even though the control would normally need to be cycled through its states of “on”, “off”, and “mixed”, the macro utility can set the control directly to the desired state.
- Related Resources for Success Criterion 4.1.5 :
4.1.6 Expose Accessible Properties:
If any of
the following properties are supported by the platform accessibility architecture, make the properties available to the accessibility platform
architecture: (Level A)
- the bounding dimensions and coordinates of onscreen elements
- font family of text
- font size of text
- foreground color of text
- background color of text.
- change state/value notifications
- selection
- highlighting
- input device focus
- direct keyboard commands
- Intent of Success Criterion 4.1.6 :
These properties are used by assistive technology to create alternative views of the user agent user interface and rendered content as well as providing alternative means for the user to interact with these items. This applies to both user agent user interface (e.g. menus and dialog boxes) and to recognized aspects of the user content (e.g. HTML script using ARIA to indicate focus on custom controls).
- Examples of Success Criterion 4.1.6 1:
- Kiara loads a new version of a popular web browser for the first time. She puts her screen reader into an "explore mode" that lets her review what is appearing on the screen. Her screen reader uses the bounding rectangle of each element to tell her that items from the menu bar all appear on the same horizontal line, which is below the window's title bar.
- Kiara is using a screen reader at a telephone call center. The Web application displays caller names in different colors depending on their banking status. Kiara needs to know this information to appropriately respond to each customer immediately, without taking the time to look up their status through other means.
-
Max uses a screen magnifier that only shows him a small amount of the screen at one time. He gives it commands to pan through different portions of a Web page, but then can give it additional commands to quickly pan back to positions of interest, such as the text matched by the recent Search operation, text that he previously selected by dragging the mouse, or the text caret, rather than having to manually pan through the document searching for them.
- Related Resources for Success Criterion 4.1.6 :
4.1.7 Timely Communication:
For APIs implemented to satisfy the requirements of UAAG 2.0, ensure that programmatic exchanges proceed at a rate such that users do not perceive a delay. (Level A)
- Intent of Success Criterion 4.1.7 :
Conveying information for accessibility can often involve extensive communication between a user agent, an accessibility API, document object model, assistive technology and end user interaction. The objective is to ensure that the end user does not perceive a delay when interacting with the user agent.
- Examples of Success Criterion 4.1.7 :
- Bonita accesses her web browser with a speech input program. She navigates to a web page and speaks the name of a link she wants to click. The link is activated with the same speed as it would be if a mouse had been used to click the link.
- Arthur is browsing a web page with a screen reader. As he tabs from link to link, the text of each link instantly appears on his braille display.
- Related Resources for Success Criterion 4.1.7 :
- @@ Editors' note: Insert something about performance and classifications.@@
Implementing Guideline 4.2 - Facilitate programmatic access to nested user agents
[Return to Guideline]
Summary: Input focus correctly transitions between nested user agents (4.2.1),users can retrieve input focus at any time (4.2.2) and input focus never gets stuck in any nested user agent (4.2.3).
4.2.1 Hand-Off Focus [former 1.9.5]:
The
user agent programmatically notifies any nested user agent(s) (e.g.
plug-ins) when active input focus moves to a nested agent. (Level A)
- Intent of Success Criterion 4.2.1:
T
- Examples of Success Criterion 4.2.1:
- A browser plug-in is installed to play a popular media format. When the user tabs to the controls for the plug-in, the user agent notifies the plug-in to handle keyboard interaction.
- Related Resources for Success Criterion 4.2.1:
4.2.2 Retrieve Focus [former 1.9.6, before that 3.11.6]:
At any time, the user is able to retrieve input focus from a nested viewport (including a nested viewport that is a user agent).(Level A)
- Intent of Success Criterion 4.2.2:
Historically keyboard users have had difficulty with nested user agents trapping keyboard focus, preventing the user from activating host browser commands including navigation and menus.
- Examples of Success Criterion 4.2.2:
- Ari is using a video hosting site where each page hosts a nested media player. He presses Tab until the focus in on the media player, then presses Enter to activate and put the keyboard focus on it. When he's finished watching the video, he presses Tab to navigate to the comments below the video, but cannot get the focus to leave the video player. He presses Alt+Left to return to the previous page, but that also fails because the video player is consuming those keystrokes. Luckily, Ari knows that Shift+Esc will return focus from a nested user agent, with or without its cooperation. Thus, even a badly behaved nested user agent cannot prevent Ari from getting on with his work.
- Related Resources for Success Criterion 4.2.2:
4.2.3 Return Focus [former 1.9.7, before that 3.11.7]:
At any time, the user agent can retrieve input focus from a nested viewport (including nested viewports that are user agents). (Level A)
- Intent of Success Criterion 4.2.3:
T
- Examples of Success Criterion 4.2.3:
- Bob has a motor impairment that impacts his use of the keyboard. The web page he is using has an iframe with content that contains 75 links. Rather than moving through all of the links in the iframe using the 'tab' key, he uses his browsers 'jump to next link in the main page' key. The focus immediately jumps to the next available link after the iframe.
- Related Resources for Success Criterion 4.2.3:
PRINCIPLE 5: Comply with applicable
specifications and conventions
@@ Editors' Note: 5.1 is being removed because it duplicated 5.3.2 @@
Implementing Guideline 5.2 - Ensure that Web-based
functionality is accessible.
[Return to Guideline]
Summary: When the browser's menus, buttons, dialogs, etc. are authored in HTML or similar standards, they need to meet W3C's Web Content Accessibility Guidelines.
5.2.1 Web-Based Accessible (Level A) :
User agent user interfaces that are rendered using Web standard technologies conform to WCAG Level "A".
(Level A)
5.2.2 Web-Based Accessible (Level AA) :
User agent user interfaces that are rendered using Web standard technologies conform to WCAG Level
"AA". (Level AA)
5.2.3 Web-Based Accessible (Level AAA) :
User agent user interfaces that are rendered using Web standard technologies conform to WCAG Level
"AAA". (Level AAA)
- Intent of Guideline 5.2:
Web-based applications which are intended to replace or enhance a desktop user agent or its functionality, but are in-fact built and rendered using standard Web technologies, are becoming increasingly common. These Web applications, windowless browsers, rich internet applications, HTML5 canvas, etc., perform similar functions to their desktop cousins and so must also conform to the accessibility requirements placed on a desktop user agent.
- Examples of Guideline 5.2:
- Success criteria 2.7.1 requires that a user agent enable a user to change settings that impact accessibility. In this case we would expect that a Web-Based user agent should also enable a user to change accessibility settings specific to its functionality, which may in some cases enhance or override that of the platform on which it is executing: window-less browser, native operating system, etc.
- Related Resources for Guideline 5.2:
- WAI-ARIA 1.0 User Agent Implementation Guide
- W3C Web Design and Applications Activity
Applicability Notes:
This guideline does not apply to non-Web-based user agent user interfaces,
but does include any parts of non-Web-based user agents that are
Web-based (e.g. help systems).
Summary: Implement the accessibility features of all the technologies you're using, such as supporting the platform's multitasking capabilities and HTML's alt attribute for images. Document your implementation.
5.3.1 Implement accessibility features of content specs:
Implement and cite in the conformance claim the accessibility
features of content
specifications. Accessibility features are those that are either (Level A) :
- identified as such in the specification or
- allow authors to satisfy a requirement of WCAG.
- Intent of Success Criterion 5.3.1:
- Most content specifications include features important to users with disabilities, and users may find it difficult or impossible to use a product that fails to support those features. Users should be able to easily discover detailed information about the user agent's adherence to accessibility standards, including those related to content such as HTML and WAI-ARIA, and should be able to do so without installing and testing the accessibility features. This will allow them to make informed decisions about whether or not to they will be able to use, and therefore should install, a new product or version of that product.
- Examples of Success Criterion 5.3.1 :
- Jordy uses a web site which uses WAI-ARIA to identify the functions of custom controls. If he used a web browser that didn't support this aspect of WAI-ARIA and expose that information to assistive technology, the web site would be unusable with his web browser. Therefore Jordy needs to choose a web browser that he knows fully supports WAI-ARIA, and he determines this by reading product documentation and UAAG conformance claims posted on the Web
- Related Resources for Success Criterion 5.3.1:
- WCAG
- HTML
- CSS
- WAI-ARIA
5.3.2 Implement Accessibility Features of platform:
Implement and cite in the conformance claim the accessibility
features of platform technology
specifications. Accessibility features are those that are either (Level A) :
- identified as such in the specification or
- allow authors to satisfy a requirement of WCAG.
- Intent of Success Criterion 5.3.2:
- Most operating systems have conventions and expectations that aid accessibility, such as keyboard behavior, support of an accessibility API, user interface design, and other standards related to accessibility. The intent of this success criteria is to ensure that user agents comply with the basic accessibility requirements of the platform in use.
If browsers and players don't seamlessly conform to platform accessibility features, then users can't easily take advantage of those features. Software that has versions for different platforms, may have to handle accessibility differently on different platforms or operating systems. In order to show that you have implemented the accessibility features of the platform correctly, these features are identified in the conformance claim.
The user should be able to easily discover detailed information about the user agent's adherence to accessibility standards, platform standards such as MSAA or JAA, and third-party standards such as ISO 9241-171, and should be able to do so without installing and testing the accessibility features.
- Examples of Success Criterion 5.3.2 :
- If you are developing for the Gnome platform, consult the Gnome Accessibility Developers Guide. For example, the Keyboard Focus section states: "Show current input focus clearly at all times. Remember that in controls that include a scrolling element, it is not always sufficient to highlight just the selected element inside that scrolling area, as it may not be visible. " If your program controls focus, make sure you conform to this accessibility guideline for focus.
In the conformance claim [link to conformance section], list the requirements you fully comply with, list the requirements you partially comply with and explain, and list the requirements you do not comply with and explain. Where applicable, this explanations can be general and cover several sections at once.
- Related Resources for Success Criterion 5.3.2:
- [APPLE-ACCESS]
- "Introduction to Accessibility Overview," Apple Computer Inc.
- [CARBON-ACCESS]
- "Introduction to Accessibility Programming Guidelines for Carbon," Apple Corporation.
- [COCOA-ACCESS]
- "Introduction to Accessibility Programming Guidelines for Cocoa," Apple Corporation.
- [EITAAC]
- "EITAAC Desktop Software standards," Electronic Information Technology Access Advisory (EITAAC) Committee.
- [GNOME-ACCESS]
- "GNOME Accessibility for Developers," C. Benson, B. Cameron, B. Haneman, S. Snider, P. O'Briain, The GNOME Accessibility Project.
- [GNOME-API]
- "Gnome Accessibility Toolkit API"
- [GNOME-KDE-KEYS]
- "Gnome/KDE Keyboard Shortcuts," Novell Corporation.
- [IBM-ACCESS]
- "Software Accessibility," IBM Special Needs Systems.
- [IEC-4WD]
- IEC/4WD 61966-2-1: Colour Measurement and Management in Multimedia Systems and Equipment - Part 2.1: Default Colour Space - sRGB. May 5, 1998.
- [ISO-TS-16071]
- "Ergonomics of human-system interaction -- Guidance on accessibility for human-computer interfaces". International Organization for Standardization.
- [JAVA-ACCESS]
- "IBM Guidelines for Writing Accessible Applications Using 100% Pure Java," R. Schwerdtfeger, IBM Special Needs Systems.
- [JAVA-API]
- " Java Accessibility Package"
- [JAVA-CHECKLIST]
- "Java Accessibility Guidelines and Checklist," IBM Special Needs Systems.
- [MACOSX-KEYS]
- "Mac OS X keyboard shortcuts," Apple Corporation.
- [MS-ENABLE]
- "Accessibility for Applications Designers," Microsoft Corporation.
- [MS-WIN7-ACCESS]
- "Engineering Software For Accessibility", Microsoft Corporation.
- [MS-KEYS]
- "Keyboard shortcuts for Windows," Microsoft Corporation.
- [NOTES-ACCESS]
- "Lotus Notes application accessibility," IBM Corporation.
- [SUN-DESIGN]
- "Designing for Accessibility," Eric Bergman and Earl Johnson. This paper discusses specific disabilities including those related to hearing, vision, and cognitive function.
- [Editors' Note: Resource links from Jim - compare and expand]
- http://www.microsoft.com/windowsxp/using/accessibility/default.mspx
- http://www.apple.com/accessibility/
- http://www.linux.org/docs/ldp/howto/Accessibility-HOWTO/linuxos.html
- http://www.linuxfoundation.org/collaborate/workgroups/accessibility/iaccessible2
- http://developer.apple.com/ue/accessibility/
- http://msdn.microsoft.com/en-us/library/dd373592%28VS.85%29.aspx
- http://msdn.microsoft.com/en-us/windows/ee815673.aspx
[@@ Editor's Note: Suzanne proposed additional SC which are holding on action items. @@]]
Summary: Render content according to the technology specification, including accessibility features (5.4.1), and let users choose how content types are handled, such as opening embedded images, videos, or documents in separate applications or saving them to disk (5.4.2, 5.4.3).
[delete all of 5.4.1 ]5.4.1 Follow Specifications:
The user agent renders content according to the technology specification, except where it would actually harm overall accessibility.
(Level A)
- Intent of Success Criterion 5.4.1:
End users and assistive technology products assume that content will be rendered in a predictable fashion. This success criterion ensures that user agents provide this level of predictability. It may be necessary to ignore aspects of the technology specification where they would actually harm, rather than improve, overall accessibility. In these cases user agent developers are encouraged to deviate from those aspects of the standard, and document the decision in their conformance claim. For example, the CSS spec says generated content should not appear in the DOM, which may mean that generated content would not be exposed to assistive technology and thus may not be accessible to blind users. User agents should instead expose the generated content through the DOM, and document their decision to ignore that aspect of the specification.
- Examples of Success Criterion 5.4.1 :
- A user agent implements the WAI-ARIA (Accessible Rich Internet Applications) standard, and the developer follows the "Implementing ARIA" document by mapping ARIA roles and events to the supported platform accessibility infrastructure (MSAA, UIA, ____, etc.). This allows a screen reader that supports the platform infrastructure to correctly support ARIA in the user agent.
- An organization creates an optional style sheet that enlarges fonts and adapts all colors for maximum contrast. They can be confident that when their Web site uses this style sheet it will work with any browser because those browsers have implemented CSS according to the CSS specification.
- Related Resources for Success Criterion 5.4.1:
5.4.2 Handle Unrendered
Technologies:
If the user agent does
not render a technology, the user can choose a way to handle content
in that technology (e.g. by launching another application or by saving it to
disk). (Level A)
- Intent of Success Criterion 5.4.2:
Users who have disabilities may have fewer options in terms of how they access the information. Information is made available in a variety of ways on the Internet, and at times a specific format may be the only way in which information is available. If the user agent cannot render that format it should let the user access that content through alternate means, such as invoking a third-party renderer or saving the file to the user's hard drive.
- Examples of Success Criterion 5.4.2 :
- Tracy has low vision and finds it much more convenient to access her bank statement electronically than on paper, even though the electronic version is in a TIFF image, a format that her browser cannot render. In this case, the browser lets her save the image to her hard drive so she can open it in another program.
- Related Resources for Success Criterion 5.4.2
5.4.3 Alternative content handlers:
The user can select content elements and have them rendered in alternative viewers. (Level AA)
- Intent of Success Criterion 5.4.3:
When accessing media content on the Web, users with disabilities sometimes find they have a richer or more accessible experience in a third-party application than using the browser's built-in facilities. In these cases they want to be able to navigate to content in their browser, then save that content to their disk or launch it in a third-party application.
- Examples of Success Criterion 5.4.3 :
- A browser supports the VIDEO tag and adds its own play and pause controls, but George prefers to view the video content in a third-party application that provides much more sophisticated navigation controls such as bookmarks, skip-forward and backwards, and the ability to speed playback without increasing pitch of the audio track. In the browser, he right-clicks on the video to display a context menu, and from that chooses "Open in…", and then chooses his preferred video player. The browser launches the player to show that video file in the browser's cache folder. The browser saves the video to a temporary location on the user's disks (or uses one already in its cache folder), then launches the player to show that file.
- [@@ Editors Note: add the MathML example @@]
In the case of streaming video that cannot be saved to disk, the browser launches the external viewer, passing it the URL to the online video.
- Related Resources for Success Criterion 5.4.3
Applicability Note:
When a rendering requirement of another specification contradicts a
requirement of UAAG 2.0, the user agent may disregard the rendering
requirement of the other specification and still satisfy this guideline.
Conformance
This section is normative.
Conformance means that the user agent satisfies the success criteria
defined in the guidelines section. This conformance section describes
conformance and lists the conformance requirements.
Conformance Requirements
In order for a Web page to conform to UAAG 2.0, one of the following levels of conformance is met
in full.
- Level A: For Level A conformance (the minimum level of conformance), the
user agent satisfies all the Level A Success Criteria.
- Level AA: For Level AA conformance, the user agent satisfies all the
Level A and Level AA Success Criteria.
- Level AAA: For Level AAA conformance, the user agent satisfies all the
Level A, Level AA and Level AAA Success Criteria.
Note 1: Although conformance can only be achieved at the stated levels,
developers are encouraged to report (in their claim) any progress toward
meeting success criteria from all levels beyond the achieved level of
conformance.
Conformance Claims (Optional)
If a conformance claim is made, the conformance claim must meet the
following conditions and include the following information (user agents
can conform to UAAG 2.0 without making a claim):
Conditions on Conformance Claims
- At least one version of the conformance claim must be published on the
web as a document meeting level "A" of WCAG 2.0. A suggested metadata
description for this document is "UAAG 2.0 Conformance Claim".
- Whenever the claimed conformance level is published (e.g. product
information website), the URI for the on-line published version of the
conformance claim must be included.
- The existence of a conformance claim does not imply that the W3C has
reviewed the claim or assured its validity.
- Claimants may be anyone (e.g. user agent developers, journalists, other
third parties).
- Claimants are solely responsible for the accuracy of their claims
(including claims that include products for which they are not
responsible) and keeping claims up to date.
- Claimants are encouraged to claim conformance to the most recent version
of the User Agent Accessibility Guidelines Recommendation.
Required Components of an UAAG 2.0 Conformance Claim
- Claimant name and affiliation.
- Date of the claim.
- Conformance level satisfied.
- User agent information: The name of the user agent and sufficient
additional information to specify the version (e.g. vendor name,
version number (or version range), required patches or updates, human
language of the user interface or documentation).
Note: If the user agent is a collection of software components (e.g. a
browser and extentions or plugins), then the name and version information must be provided
separately for each component, although the conformance claim will treat
them as a whole. As stated above, the Claimant has sole responsibility
for the conformance claim, not the developer of any of the software
components.
- Included Technologies: A list of the web content technologies
(including version numbers) rendered by the user agent that the Claimant
is including in the conformance claim. By including a web content
technology, the Claimant is claiming that the user agent meets the
requirements of UAAG 2.0 during the rendering of web content using that
web content technology.
Note 1: Web content technologies may be a combination of constituent web
content technologies. For example, an image technology (e.g. PNG) might
be listed together with a markup technology (e.g. HTML) since web
content in the markup technology is used make web content in the image
technology accessible (e.g. a PNG graph is made accessible using an
HTML table).
- Excluded Technologies: A list of any web content technologies produced
by the user agent that the Claimant is excluding from the
conformance claim. The user agent is not required to meet the
requirements of UAAG 2.0 during the production of the web content
technologies on this list.
- Declarations: For each success criterion:
A declaration of whether or not the success criterion has been
satisfied; or
A declaration that the success criterion is not applicable and a
rationale for why not.
- Platform(s): The platform(s) upon which the user agent was evaluated:
For user agent platform(s) (used to evaluate web-based user agent user
interfaces): provide the name and version information of the user agent(s).
For platforms that are not user agents (used to evaluate non-web-based
user agent user interfaces) provide: The name and version information of
the platform(s) (e.g. operating system, etc.) and the name and
version of the platform accessibility architecture(s) employed.
Optional Components of an UAAG 2.0 Conformance Claim
A description of how the UAAG 2.0 success criteria were met where this
may not be obvious.
"Progress Towards Conformance" Statement
Developers of user agents that do not yet conform fully to a particular
UAAG 2.0 conformance level are encouraged to publish a statement on
progress towards conformance. The progress statement is the same as a
conformance claim except an UAAG 2.0
conformance level that is being progressed towards, rather than one
already satisfied, and report progress on success criteria not yet
met. Authors of "Progress Towards Conformance" Statement are solely
responsible for the accuracy of their statements. Developers are
encouraged to provide expected timelines for meeting outstanding success
criteria within the Statement.
Disclaimer
Neither W3C, WAI, nor UAWG take any responsibility for any aspect or
result of any UAAG 2.0 conformance claim that has not been published
under the authority of the W3C, WAI, or UAWG.
This glossary is normative.
- accelerator key
- see keyboard command
- activate
- To carry out the behaviors associated
with an enabled element in the rendered
content or a component of the user agent user
interface.
- active input focus
- see focus
- active selection
- see focus
- alternative content
- Content that can be used in place of default content that may not be universally accessible. Alternative content fulfills the same purpose as the original content. Examples include text alternatives for non-text content, captions for audio, audio descriptions for video, sign language for audio, media alternatives for time-based media. See WCAG for more information.
- alternative content
stack
- A set of alternative content items. The items may be mutually exclusive (e.g.
regular contrast graphic vs. high contrast graphic) or non-exclusive
(e.g. caption track that can play at the same time as a sound
track).
- animation
- Graphical content rendered to automatically change over time, giving the user a visual perception of movement. Examples include video, animated images, scrolling text, programmatic animation (e.g. moving or replacing rendered objects).
-
- application
programming interface (API), (conventional input/output/device
API)
- An application programming interface (API) defines how
communication may take place between applications.
- assistive technology
- An assistive
technology:
- relies on services (such as retrieving Web
resources and parsing markup) provided by one or more other
"host" user agents. Assistive technologies communicate data and
messages with host user agents by using and monitoring APIs.
- provides services beyond those offered by the host user agents to
meet the requirements of users with disabilities. Additional
services include alternative renderings (e.g. as synthesized
speech or magnified content), alternative input methods (e.g.
voice), additional navigation or orientation mechanisms, and
content transformations (e.g. to make tables more accessible).
Examples of assistive technologies that are important in the context
of UAAG 2.0 include the following:
- screen magnifiers, which are used by people with visual
disabilities to enlarge and change colors on the screen to improve
the visual readability of rendered text and images.
- screen readers, which are used by people who are blind or have
reading disabilities to read textual information through
synthesized speech or braille displays.
- voice recognition software, which are used by some people who have
physical disabilities to simulate the keyboard and mouse.
- alternative keyboards, which are used by some people with
physical disabilities to simulate the keyboard and mouse.
- alternative pointing devices, which are used by some people with
physical disabilities to simulate mouse pointing and button
activations.
- Beyond UAAG 2.0, assistive technologies consist
of software or hardware that has been specifically designed to assist
people with disabilities in carrying out daily activities. These
technologies include wheelchairs, reading machines, devices for
grasping, text telephones, and vibrating pagers. For example, the
following very general definition of "assistive technology device"
comes from the (U.S.) Assistive Technology Act of 1998 [AT1998]:
Any item, piece of equipment, or product system, whether acquired
commercially, modified, or customized, that is used to increase,
maintain, or improve functional capabilities of individuals with
disabilities.
- audio
- The technology of sound reproduction. Audio can be created synthetically (including speech synthesis), streamed from a live source (such as a radio broadcast), or recorded from real world sounds.
-
- audio description - (described video, video description or descriptive narration)
- An equivalent alternative that takes the form of narration added to
the audio to describe important visual details
that cannot be understood from the main soundtrack alone. Audio
description of video provides information about actions, characters,
scene changes, on-screen text, and other visual content. In standard
audio description, narration is added during existing pauses in
dialogue. In extended audio
description, the video is paused so that there is time to add
additional description.
- authors
- The people who have worked either alone or collaboratively to create
the content (e.g. content authors, designers, programmers,
publishers, testers).
- author styles
- Style property
values that are set by the author as part of the content.
- background images
- Images that are rendered on the base background.
- base
background
- The background of the content as a whole, such that
no content may be layered behind it. In graphics applications the base
background is often referred to as the canvas.
- blinking
text
- Text whose visual rendering alternates between visible and invisible
at any rate of change.
- captions (caption)
- An equivalent alternative that takes the form of text presented and synchronized with time-based media to provide not only the speech, but also non-speech information conveyed through sound, including meaningful sound effects and identification of speakers. In some
countries, the term "subtitle" is used to refer to dialogue only and
"captions" is used as the term for dialogue plus sounds and speaker
identification. In other countries, "subtitle" (or its translation) is
used to refer to both. Open captions are captions that are
always rendered with a visual track; they cannot be turned off.
Closed captions are captions that may be turned on and off.
The captions requirements of UAAG 2.0 assume that the user agent
can recognize the captions as such.
Note: Other terms that include the word "caption" may
have different meanings in UAAG 2.0. For instance, a "table
caption" is a title for the table, often positioned graphically above
or below the table. In UAAG 2.0, the intended meaning of "caption"
will be clear from context.
- collated text
transcript
- A collated text transcript is a text equivalent of a movie or
other animation. It is the combination of the text transcript of the audio track and the text equivalent
of the visual track. For example, a
collated text transcript typically includes segments of spoken dialogue
interspersed with text descriptions of the key visual elements of a
presentation (actions, body language, graphics, and scene changes). See
also the definitions of text
transcript and audio description. Collated
text transcripts are essential for people who are deaf-blind.
- command, direct command, direct navigation command, direct activation command, linear navigation command
, spacial (directional) command, structural navigation command
- direct navigation commands move focus to a specified item regardless of which currently has the focus
- direct activation commands activate a specified item regardless of which currently has the focus; they may move the focus to the item before immediately activating it
- linear navigation commands (sometimes called logical or sequential navigation commands) move forwards and backwards through a list of items
- structural navigation commands move forwards, backwards, up and down a hierarchy
- spatial commands (sometimes called directional commands), require the user to be cognizant of the spatial arrangement of items on the screen:
- spatial navigation commands move from one item to another based on direction on the screen
- spatial manipulation commands resize or reposition an item on the screen
- content (web content)
- Information and sensory experience to be communicated to the user by means of a user agent, including code or markup that defines the content's structure, presentation, and interactions [adapted from WCAG 2.0]
empty
content (which may be alternative content) is
either a null value or an empty string (e.g. one that is zero
characters long). For instance, in HTML, alt=""
sets the
value of the alt
attribute to the empty string. In some
markup languages, an element may have empty content (e.g. the
HR
element in HTML).
- cursor
- see focus
- default
- see properties
- direct command, direct navigation command, direct activation command, linear navigation command
, spacial (directional) command, structural navigation command
-
document character set
- The internal representation of data in the source content by a user agent.
-
document object, (Document Object Model, DOM)
- The Document Object Model is a platform- and language-neutral interface that allows programs and scripts to dynamically access and update the content, structure and style of documents. The document can be further processed and the results of that processing can be incorporated back into the presented page. This is an overview of DOM-related materials here at W3C and around the web:
http://www.w3.org/DOM/#what.
- document source, (text source)
- Text the user agent renders upon user request to view the source of specific viewport content (e.g. selected content, frame, page).
- documentation
- Any information that supports the use of a user agent. This information may be found, for example, in manuals, installation instructions, the help system, and tutorials. Documentation may be distributed (e.g. as files installed as part of the installation, some parts may be delivered on CD-ROM, others on the Web). See guideline 5.3 for information about
documentation.
- element, element type
- UAAG 2.0 uses the terms "element" and "element
type" primarily in the sense employed by the XML 1.0 specification
([XML], section 3): an element
type is a syntactic construct of a document type definition (DTD) for
its application. This sense is also relevant to structures defined by
XML schemas. UAAG 2.0 also uses the term "element" more generally
to mean a type of content (such as video or sound) or a logical
construct (such as a header or list).
- empty content
- see content
- enabled element, disabled
element
-
An element with associated behaviors that can be activated through the user interface or through an API. The set of elements that a user agent enables is generally derived from, but is not limited to, the set of elements defined by implemented markup languages. A disabled element is a potentially enabled element that is not currently available for activation (e.g. a "grayed out" menu item).
- equivalent alternative
- Acceptable substitute content that a user may not be able to access. An equivalent alternative fulfills essentially the same function or purpose as the original content upon presentation:
- text alternative: text that is available via the operating environment that is used in place of non-text content (e.g. text equivalents for images, text transcripts for audio tracks, or collated text transcripts for a movie). [from WCAG 2.0]
- full text alternative for synchronized media including any interaction: document including correctly sequenced text descriptions of all visual settings, actions, speakers, and non-speech sounds, and transcript of all dialogue combined with a means of achieving any outcomes that are achieved using interaction (if any) during the synchronized media. [from WCAG 2.0]
- synchronized alternatives: present essential audio information visually (i.e. captions) and essential video information in an auditory manner (i.e. audio descriptions).
[from ATAG 2.0]
- events and
scripting, event handler, event type
- User agents often perform a task when an event
having a particular "event type" occurs, including a user interface
event, a change to content, loading of content, or a request from the
operating environment.
Some markup languages allow authors to specify that a script, called an
event
handler, be executed when an event of a given type occurs. An
event handler is explicitly associated with an
element through scripting, markup or the DOM.
- explicit user request
- An interaction by the user through the user
agent user interface, the focus, or the selection. User requests are made, for example, through user
agent user interface controls and keyboard commands. Some examples of explicit user requests include when the user selects "New viewport," responds "yes" to a prompt in the user agent's user interface, configures the user agent to behave in a certain way, or changes the selection or focus with the keyboard or pointing device. Note: Users can make errors when interacting with the user agent. For example, a user may inadvertently respond "yes" to a prompt instead of "no." This type of error is considered an explicit user request.
- focus (active input focus, active selection, cursor, focus cursor, focusable element, highlight, inactive input focus, inactive selection, input focus, keyboard focus, pointer, pointing device focus, selection, split focus, text cursor)
Hierarchical Summary of some focus terms
- Input Focus (active/inactive)
- Keyboard Focus (active/inactive)
- Cursor (active/inactive)
- Focus cursor (active/inactive)
- Text cursor (active/inactive)
- Pointing device focus (active/inactive)
- active input focus
- The input focus location in the active viewport. The active focus is in the active viewport, while the inactive input focus is the inactive viewport. The active input focus is usually visibly indicated. In UAAG 2.0 "active input focus" generally refers to the active keyboard input focus. @@ Editors' Note: this term is not used in the document other than the glossary.@@
- active selection
- The selection that will currently be affected by a user command, as opposed to selections in other viewports, called inactive selections, which would not currently be affected by a user command. @@ Editors' Note: this term is not used in the document other than the glossary.@@
- conform
- see support
- cursor
- Visual indicator showing where keyboard input will occur. There are two types of cursors: focus cursor (e.g. the dotted line around a button) and text cursor (e.g. the flashing vertical bar in a text field, also called a 'caret'). Cursors are active when in the active viewport, and inactive when in an inactive viewport.
- focus cursor
- Indicator that highlights a user interface element to show that it has keyboard focus, e.g. a dotted line around a button, or brightened title bar on a window. There are two types of cursors: focus cursor (e.g. the dotted line around a button) and text cursor (e.g. the flashing vertical bar in a text field).
- focusable element
- Any element capable of having input focus, e.g. link, text box, or menu item. In order to be accessible and fully usable, every focusable element should take keyboard focus, and ideally would also take pointer focus.
- highlight, highlighted, highlighting
- Emphasis indicated through the user interface. For example, user agents highlight content that is selected,focused, or matched by a search operation. Graphical highlight mechanisms include dotted boxes, changed colors or fonts, underlining, magnification, and reverse video. Synthesized speech highlight mechanisms include alterations of voice pitch and volume ("speech prosody"). User interface items may also be highlighted, for example a specific set of foreground and background colors for the title bar of the active window. Content that is highlighted may or may not be a selection.
- inactive input focus
- An input focus location in an inactive viewport such as a background window or pane. The inactive input focus location will become the active input focus location when input focus returns to that viewport. An inactive input focus may or may not be visibly indicated.
- inactive selection
- A selection that does not have the input focus and thus does not take input events.
- input focus
- The place where input will occur if a viewport is active. Examples include keyboard focus and pointing device focus. Input focus can also be active (in the active viewport) or inactive (in an inactive viewport).
- keyboard focus
- The screen location where keyboard input will occur if a viewport is active. Keyboard focus can be active (in the active viewport) or inactive (in an inactive viewport).
- pointer
- Visual indicator showing where pointing device input will occur. The indicator can be moved with a pointing device or emulator such as a mouse, pen tablet, keyboard-based mouse emulator, speech-based mouse commands, or 3-D wand. A pointing device click typically moves the input focus to the pointer location. The indicator may change to reflect different states.When touch screens are used, the "pointing device" is a combination of the touch screen and the user's finger or stylus. On most systems there is no pointer (on-screen visual indication) associated with this type of pointing device.
- pointing device focus
- The screen location where pointer input will occur if a viewport is active. There can be multiple pointing device foci for example when using a screen sharing utility there is typically one for the user's physical mouse and one for the remote mouse. @@ Editors' Note: this term is not used in the document other than the glossary.@@
- selection
- A user agent mechanism for identifying a (possibly empty) range of content that will be the implicit source or target for subsequent operations. The selection may be used for a variety of purposes, including for cut-and-paste operations, to designate a specific element in a document for the purposes of a query, and as an indication of point of regard (e.g. the matched results of a search may be automatically selected). The selection should be highlighted in a distinctive manner. On the screen, the selection may be highlighted in a variety of ways, including through colors, fonts, graphics, and magnification. When rendered using synthesized speech, the selection may be highlighted through changes in pitch, speed, or prosody.
- split focus
- A state when the user could be confused because the input focus is separated from something it is usually linked to, such as being at a different place than the selection or similar highlighting, or has been scrolled outside of the visible portion of the viewport. @@ Editors' Note: this term is not used in the document other than the glossary.@@
- text cursor
- Indicator showing where keyboard input will occur in text (e.g. the flashing vertical bar in a text field, also called a caret).
- @@ Editor's Note: Need to find the hrefs to these definitions and fix them. @@
- globally, global configuration
- @@ Editors' Note: Needs to be written@@
- graphical
- Information (e.g. text, colors, graphics, images, and animations)
rendered for visual consumption.
- highlight, highlighted, highlighting
- see focus
- image
- Pictorial content that is static (i.e. not moving or changing). See also the definition of animation.
- implement
- see support
- important elements
- This specification intentionally does not identify
which "important elements" must be navigable because this will vary by
specification. What constitutes "efficient navigation" may depend on a
number of factors as well, including the "shape" of content (e.g.
sequential navigation of long lists is not efficient) and desired
granularity (e.g. among tables, then among the cells of a given
table). Refer to the Implementing document [Implementing UAAG 2.0] for information
about identifying and navigating important elements. @@ Editors' Note: Update links
- inactive input focus
- see focus
- inactive selection
- see focus
- informative (non-normative)
- see normative
- input configuration
- The set of bindings
between user agent functionalities and user
interface input mechanisms (e.g. menus, buttons, keyboard keys,
and voice commands). The default input configuration is the set of
bindings the user finds after installation of the software. Input
configurations may be affected by author-specified bindings (e.g.
through the
accesskey
attribute of HTML 4 [HTML4]).
- input focus
- see focus
-
- keyboard command (keyboard binding,keyboard shortcuts or accelerator keys)
- Commands tied to particular UI controls or application functions, allowing the user to navigate-to or activate them without traversing any intervening controls (e.g. "ctrl"+"S" to save a document). It is sometimes useful to distinguish keyboard commands that are associated with controls that are rendered in the current context (e.g. "alt"+"D" to move focus to the address bar) from those that may be able to activate program functionality that is not associated with any currently rendered controls (e.g. "F1" to open the Help system). Keyboard commands help users accelerate their selections.
- keyboard focus
- see focus
- natural language
- Natural language is spoken, written, or signed human
language such as French, Japanese, and American Sign Language. On the
Web, the natural language of content may be
specified by markup or HTTP headers. Some examples include the
lang
attribute in HTML 4 ([HTML4] section 8.1), the xml:lang
attribute in XML 1.0 ([XML], section 2.12), the hreflang
attribute for links in HTML 4 ([HTML4],
section 12.1.5), the HTTP Content-Language header ([RFC2616], section 14.12)
and the Accept-Language request header ([RFC2616], section 14.4).
See also the definition of script.
- non-text content (non-text element, non-text equivalent)
- see text
- normative, informative (non-normative) [WCAG 2.0, ATAG
2.0]
- What is identified as "normative" is required for conformance (noting that one may conform in a
variety of well-defined ways to UAAG 2.0). What is identified as
"informative" (or, "non-normative") is never required for
conformance.
- notify
- To make the user aware of events or status changes. Notifications can occur within the user agent user interface (e.g. a status bar) or within the content display. Notifications may be passive and not require user acknowledgment, or they may be presented in the form of a prompt requesting a user response (e.g. a confirmation dialog).
- operating environment
- The term "operating environment" refers to the
environment that governs the user agent's operation, whether it is an
operating system or a programming language environment such as
Java.
- override
- In UAAG 2.0, the term "override" means that one
configuration or behavior preference prevails over another. Generally,
the requirements of UAAG 2.0 involve user preferences prevailing
over author preferences and user agent default settings and behaviors.
Preferences may be multi-valued in general (e.g. the user prefers blue
over red or yellow), and include the special case of two values (e.g.
turn on or off blinking text content).
- placeholder
- A placeholder is content generated by the user agent
to replace author-supplied content. A placeholder may be generated as
the result of a user preference (e.g. to not render images) or as repair content (e.g. when an
image cannot be found). A placeholder can be any type of content,
including text, images, and audio cues. A placeholder should identify
the technology of the replaced object.
Placeholders appear in the alternative content stack.
- platform accessibility
architecture
- A programmatic interface that is engineered to enhance
communication between mainstream software applications and assistive
technologies (e.g. MSAA, UI Automation, and IAccessible2 for Windows applications, AXAPI for MacOSX applications, Gnome Accessibility Toolkit API for Gnome applications, Java Access for Java applications). On some platforms it may be conventional to enhance
communication further via implementing a DOM.
- plug-in [ATAG 2.0]
- A plug-in is a program that runs as part of the user
agent and that is not part of content. Users
generally choose to include or exclude plug-ins from their user
agents.
- point of regard
- The point of regard is the position in rendered content that the user
is presumed to be viewing. The dimensions of the point of regard may
vary. For example, it may be a point (e.g. a moment during an audio
rendering or a cursor position in a graphical rendering), or a range of
text (e.g. focused text), or a two-dimensional area (e.g. content
rendered through a two-dimensional graphical viewport). The point of
regard is almost always within the viewport, but it may exceed the
spatial or temporal dimensions of the
viewport (see the definition of rendered content for more
information about viewport dimensions). The point of regard may also
refer to a particular moment in time for content that changes over time
(e.g. an audio-only
presentation). User agents may determine the point of regard in a
number of ways, including based on viewport position in content, keyboard focus, and selection. The stability of the point
of regard is addressed by [@@ Editors' Note: Need reference here@@].
- pointer
- see focus
- pointing device focus
- see focus
- profile
- A profile is a named and persistent representation
of user preferences that may be used to configure a user agent.
Preferences include input configurations, style preferences, and
natural language preferences. In operating environments
with distinct user accounts, profiles enable users to reconfigure
software quickly when they log on. Users may share their profiles with
one another.Platform-independent profiles are useful for those who use the same user agent on different devices.
- prompt [ATAG
2.0]
- Any user-agent-initiated request for a decision or piece of
information from a user.
- properties, values, and
defaults
- A user agent renders a document by applying
formatting algorithms and style information to the document's elements.
Formatting depends on a number of factors, including where the document
is rendered (e.g. on screen, on paper, through loudspeakers, on a braille
display, on a mobile device). Style information (e.g. fonts, colors,
synthesized speech prosody) may come from the elements themselves
(e.g. certain font and phrase elements in HTML), from style sheets, or
from user agent settings. For the purposes of these guidelines, each
formatting or style option is governed by a property and each property
may take one value from a set of legal values. Generally in UAAG 2.0, the term "property"
has the meaning defined in CSS 2 ([CSS2], section 3). A
reference to "styles" in UAAG 2.0 means a set of style-related
properties. The value given to a property by a user agent at
installation is the property's default value.
- recognize
- Authors encode information in many ways, including
in markup languages, style sheet languages, scripting languages, and
protocols. When the information is encoded in a manner that allows the
user agent to process it with certainty, the user agent can "recognize"
the information. For instance, HTML allows authors to specify a heading
with the
H1
element, so a user agent that implements HTML
can recognize that content as a heading. If the author creates a
heading using a visual effect alone (e.g. just by increasing the font
size), then the author has encoded the heading in a manner that does
not allow the user agent to recognize it as a heading. Some requirements of UAAG 2.0 depend on content roles, content
relationships, timing relationships, and other information supplied by
the author. These requirements only apply when the author has encoded
that information in a manner that the user agent can recognize. See the
section on conformance for more information
about applicability. User agents will rely heavily on information that the
author has encoded in a markup language or style sheet language. Behaviors, style, meaning encoded in a script, and markup in an unfamiliar XML
namespace may not be recognized by the user agent as easily or at all.
- rendered content, rendered
text
- Rendered content is the part of content that the user agent makes
available to the user's senses of sight and hearing (and only those
senses for the purposes of UAAG 2.0). Any content that causes an
effect that may be perceived through these senses constitutes rendered
content. This includes text characters, images, style sheets, scripts,
and any other content that, once processed, may be perceived
through sight and hearing.
- The term "rendered text" refers to text
content that is rendered in a way that communicates information about
the characters themselves, whether visually or as synthesized
speech.
- In the context of UAAG 2.0, invisible
content is content that is not rendered but that may
influence the graphical rendering (i.e. layout) of other content.
Similarly, silent content is content that
is not rendered but that may influence the audio rendering of other
content. Neither invisible nor silent content is considered rendered
content.
- repair content, repair text
- Content generated by the user agent to correct an error
condition. "Repair text" refers to the text portion of repair
content. Error conditions that may lead to the generation of
repair content include:
- Erroneous or incomplete content (e.g. ill-formed markup, invalid
markup, or missing alternative content
that is required by format specification);
- Missing resources for handling or rendering content (e.g. the
user agent lacks a font family to display some characters, or the
user agent does not implement a particular scripting language).
UAAG 2.0 does not require user agents to include repair content
in the document object. Repair content
inserted in the document object should conform to the Web Content
Accessibility Guidelines 1.0 [WCAG10]. For more
information about repair techniques for Web content and software, refer
to "Techniques for Authoring Tool Accessibility Guidelines 1.0"
[ATAG10-TECHS].
- script
- In UAAG 2.0, the term "script" almost always
refers to a scripting (programming) language used to create dynamic Web
content. However, in guidelines referring to the written (natural)
language of content, the term "script" is used as in Unicode [UNICODE] to mean "A
collection of symbols used to represent textual information in one or
more writing systems."
- Information encoded in (programming) scripts may be
difficult for a user agent to recognize. For
instance, a user agent is not expected to recognize that, when
executed, a script will calculate a factorial. The user agent will be
able to recognize some information in a script by virtue of
implementing the scripting language or a known program library (e.g.
the user agent is expected to recognize when a script will open a
viewport or retrieve a resource from the Web).
- selection, current
selection
- see focus
- serial access, sequential navigation
- One-dimensional access to
rendered content. Some examples of serial access include listening to
an audio stream or watching a video (both of which involve one temporal
dimension), or reading a series of lines of braille one line at a time
(one spatial dimension). Many users with blindness have serial access
to content rendered as audio, synthesized speech, or lines of braille.
The expression "sequential navigation" refers to navigation through
an ordered set of items (e.g. the enabled
elements in a document, a sequence of lines or pages, or a sequence
of menu options). Sequential navigation implies that the user cannot
skip directly from one member of the set to another, in contrast to
direct or structured navigation. Users with blindness or some users
with a physical disability may navigate content sequentially (e.g. by
navigating through links, one by one, in a graphical viewport with or
without the aid of an assistive technology). Sequential navigation is
important to users who cannot scan rendered content visually for
context and also benefits users unfamiliar with content. The increments
of sequential navigation may be determined by a number of factors,
including element type (e.g. links only), content structure (e.g.
navigation from heading to heading), and the current navigation context
(e.g. having navigated to a table, allow navigation among the table
cells).
Users with serial access to content or who navigate sequentially may
require more time to access content than users who use direct or
structured navigation.
- style grouping
- A collection of content that can be assigned to a set of presentation properties. Style groupings can be defined in three ways:
- Language: The content definition language identifies groupings of content as part of a document's semantic structure to support generic separation of content from presentation, e.g. headings, lists, paragraphs etc.
- Author: The author defines groupings of content to assign presentation properties that enhance the meaning of the document, e.g. content classes, spans and divisions etc.
- User: The user defines groupings of content to assign presentation properties to meet adaptation needs.
- style profile
-
An identifiable collection of style rules is a style profile.
- style rule
- An assignment of presentation properties to a style profile is a style rule.
- support, implement, conform
- Support, implement,
and conform all refer to what a developer has designed a user agent
to do, but they represent different degrees of specificity. A user
agent "supports" general classes of objects, such as "images" or
"Japanese." A user agent "implements" a specification (e.g. the PNG
and SVG image format specifications or a particular scripting
language), or an API
(e.g. the DOM API) when it has been programmed to follow all or part
of a specification. A user agent "conforms to" a specification when it
implements the specification and satisfies its conformance
criteria.
- synchronize
- The act
of time-coordinating two or more presentation components (e.g. a visual track with captions, or
several tracks in a multimedia presentation). For Web content
developers, the requirement to synchronize means to provide the data
that will permit sensible time-coordinated rendering by a user agent.
For example, Web content developers can ensure that the segments of
caption text are neither too long nor too short, and that they map to
segments of the visual track that are appropriate in length. For user
agent developers, the requirement to synchronize means to present the
content in a sensible time-coordinated fashion under a wide range of
circumstances including technology constraints (e.g. small text-only
displays), user limitations (e.g. slow reading speeds, large font sizes,
high need for review or repeat functions), and content that is
sub-optimal in terms of accessibility.
- technology (web content technology) [WCAG 2.0, ATAG
2.0]
- A mechanism for encoding instructions to be rendered, played or
executed by user agents. Web Content
technologies may include markup languages, data formats, or programming
languages that authors may use alone or in
combination to create end-user experiences that range from static Web
pages to multimedia presentations to dynamic Web applications. Some
common examples of Web content technologies include HTML, CSS, SVG,
PNG, PDF, Flash, and JavaScript.
- text (text content, non-text
content,
text element, non-text
element, text
equivalent, non-text equivalent )
- Text used by itself
refers to a sequence of characters from a markup language's document character set.
Refer to the "Character Model for the World Wide Web" [CHARMOD] for more
information about text and characters. Note: UAAG 2.0 makes use of other terms that include the word "text" that
have highly specialized meanings: collated text
transcript, non-text content, text content, non-text element, text element, text equivalent, and text transcript.
Atext element adds text
characters to either content or the user
interface. Both in the Web Content Accessibility Guidelines 2.0 [WCAG20] and in UAAG 2.0, text elements are presumed to produce text that can be
understood when rendered visually, as synthesized speech, or as
Braille. Such text elements benefit at least these three groups of
users:
- visually-displayed text benefits users who are deaf and adept in
reading visually-displayed text;
- synthesized speech benefits users who are blind and adept in use
of synthesized speech;
- braille benefits users who are blind, and possibly deaf-blind,
and adept at reading braille.
A text element may consist of both text and non-text data. For
instance, a text element may contain markup for style (e.g. font size
or color), structure (e.g. heading levels), and other semantics. The
essential function of the text element should be retained even if style
information happens to be lost in rendering. A user agent may have to process a text element in order to have
access to the text characters. For instance, a text element may consist
of markup, it may be encrypted or compressed, or it may include
embedded text in a binary format (e.g. JPEG).
Text content is content that is composed of one or more text
elements. A text
equivalent (whether in content or the user
interface) is an equivalent composed of
one or more text elements. Authors generally provide text equivalents
for content by using the alternative content
mechanisms of a specification.
A non-text
element is an element (in content or the user
interface) that does not have the qualities of a text element.
Non-text
content is composed of one or more non-text elements. A
non-text equivalent (whether in content or the user interface) is an
equivalent composed of
one or more non-text elements.
- text decoration
- Any
stylistic effect that the user agent may apply to visually rendered text that does not
affect the layout of the document (i.e. does not require reformatting
when applied or removed). Text decoration mechanisms include underline,
overline, and strike-through.
- text format
- Any media object given an Internet media type of
"text" (e.g. "text/plain", "text/html", or "text/*") as defined in RFC
2046 [RFC2046], section 4.1, or
any media object identified by Internet media type to be an XML
document (as defined in [XML], section 2) or SGML
application. Refer, for example, to Internet media types defined in
"XML Media Types" [RFC3023].
- text transcript
- A text equivalent of audio
information (e.g. an audio-only presentation
or the audio track of a movie or other
animation). A text transcript provides text for both spoken words and non-spoken
sounds such as sound effects. Text transcripts make audio information
accessible to people who have hearing disabilities and to people who
cannot play the audio. Text transcripts are usually created by hand but
may be generated on the fly (e.g. by voice-to-text converters). See
also the definitions of captions and collated text
transcripts.
- track (audio track or
visual track)
- Content rendered as sound through an
audio viewport. The audio track may be all
or part of the audio portion presentation (e.g. each instrument may
have a track, or each stereo channel may have a track). Also see definition of visual track
- user agent
- A user agent is any software that retrieves, renders
and facilitates end user interaction with Web content.
- user agent default styles
- User agent default styles are style property
values applied in the absence of any author or user styles. Some
markup languages specify a default rendering for content in that markup
language; others do not. For example, XML 1.0
[XML]
does not specify default styles for XML documents.
HTML 4 [HTML4] does not specify
default styles for HTML documents, but the CSS 2 [CSS2]
specification suggests a sample
default style sheet for HTML 4 based on current practice.
- user interface, user interface
control
- For the purposes of UAAG 2.0, user interface
includes both:
- the user agent user
interface, i.e. the controls (e.g. menus, buttons,
prompts, and other components for input and output) and mechanisms
(e.g. selection and focus) provided by the user agent ("out of the
box") that are not created by content.
- the "content user interface," i.e. the enabled elements that are
part of content, such as form controls, links, and applets.
The document distinguishes them only where required for clarity. For
more information, see the section on requirements for content, for user
agent features, or both @@.
The term "user interface control" refers to a component of the user
agent user interface or the content user interface, distinguished where
necessary.
- user styles
- User styles are style property
values that come from user interface settings, user style sheets,
or other user interactions.
- values
- see properties
- view, viewport
- The user agent renders content through one or
more viewports. Viewports include windows, frames, pieces of paper,
loudspeakers, and virtual magnifying glasses. A viewport may contain
another viewport (e.g. nested frames). User
agent user interface controls such as prompts, menus, and alerts
are not viewports.
Graphical and tactile viewports have two spatial dimensions. A viewport may also
have temporal dimensions, for instance when audio, speech, animations,
and movies are rendered. When the dimensions (spatial or temporal) of
rendered content exceed the dimensions of the viewport, the user agent
provides mechanisms such as scroll bars and advance and rewind controls
so that the user can access the rendered content "outside" the
viewport. Examples include: when the user can only view a portion of a
large document through a small graphical viewport, or when audio
content has already been played.
When several viewports coexist, only one has the current focus at a given moment.
This viewport is highlighted to make it stand out.
User agents may render the same content in a variety of ways; each
rendering is called a view. For instance, a user agent may
allow users to view an entire document or just a list of the document's
headers. These are two different views of the document.
top-level viewports are
viewports that are not contained within other user agent viewports.
- visual-only
presentation
- A visual-only presentation is content consisting
exclusively of one or more visual
tracks presented concurrently or in series. A silent movie is an
example of a visual-only presentation.
- visual track
- A visual object is content rendered through a
graphical viewport. Visual objects include
graphics, text, and visual portions of movies and other animations. A
visual track is a visual object that is intended as a whole or partial
presentation. A visual track does not necessarily correspond to a
single physical object or software object.
- voice browser
- From "Introduction and Overview of W3C Speech
Interface Framework" [VOICEBROWSER]: "A
voice browser is a device (hardware and software) that interprets voice
markup languages to generate voice output, interpret voice input, and
possibly accept and produce other modalities of input and output."
- web resource
- Anything that can be identified by a Uniform Resource Identifier
(URI).
Appendix B: How to refer to
UAAG 2.0 from other documents
This section is informative.
There are two recommended ways to refer to the "User Agent Accessibility
Guidelines 2.0" (and to W3C documents in general):
- References to a specific version of "User Agent Accessibility
Guidelines 2.0." For example, use the "this version" URI to
refer to the current document:
http://www.w3.org/TR/2010/WD-UAAG20-20100617/
- References to the latest version of "User Agent Accessibility
Guidelines 2.0." Use the "latest version" URI to refer to
the most recently published document in the series:
http://www.w3.org/TR/UAAG20/.
In almost all cases, references (either by name or by link) should be to
a specific version of the document. W3C will make every effort to make UAAG 2.0 indefinitely available at its original address in its original form.
The top of UAAG 2.0 includes the relevant catalog metadata for specific
references (including title, publication date, "this version" URI,
editors' names, and copyright information).
An XHTML 1.0 paragraph including a reference to this specific document
might be written:
<p>
<cite><a href="http://www.w3.org/TR/2010/WD-UAAG20-20100617/">
"User Agent Accessibility Guidelines 2.0,"</a></cite>
J. Allan, K. Ford, J. Spellman, eds.,
W3C Recommendation, http://www.w3.org/TR/ATAG20/.
The <a href="http://www.w3.org/TR/ATAG20/">latest version</a> of this document is available at http://www.w3.org/TR/ATAG20/.</p>
For very general references to this document (where stability of content
and anchors is not required), it may be appropriate to refer to the latest
version of this document. Other sections of this document explain how to build a conformance
claim.
Appendix C: References
This section is informative.
For the latest version of any W3C specification please
consult the list of W3C Technical Reports at
http://www.w3.org/TR/. Some documents listed below may have been superseded
since the publication of UAAG 2.0.
Note: In UAAG 2.0, bracketed labels such as
"[WCAG20]" link to the corresponding entries in this section. These labels
are also identified as references through markup.
- [CSS1]
- "Cascading Style
Sheets (CSS1) Level 1 Specification," B. Bos, H. Wium Lie,
eds., 17 December 1996, revised 11 January 1999. This W3C
Recommendation is http://www.w3.org/TR/1999/REC-CSS1-19990111.
- [CSS2]
- "Cascading Style
Sheets, level 2 (CSS2) Specification," B. Bos, H. Wium Lie,
C. Lilley, and I. Jacobs, eds., 12 May 1998. This W3C Recommendation is
http://www.w3.org/TR/1998/REC-CSS2-19980512/.
- [DOM2CORE]
- "Document
Object Model (DOM) Level 2 Core Specification," A. Le Hors,
P. Le Hégaret, L. Wood, G. Nicol, J. Robie, M. Champion, S. Byrne,
eds., 13 November 2000. This W3C Recommendation is
http://www.w3.org/TR/2000/REC-DOM-Level-2-Core-20001113/.
- [DOM2STYLE]
- "Document
Object Model (DOM) Level 2 Style Specification," V. Apparao,
P. Le Hégaret, C. Wilson, eds., 13 November 2000. This W3C
Recommendation is
http://www.w3.org/TR/2000/REC-DOM-Level-2-Style-20001113/.
- [INFOSET]
- "XML
Information Set," J. Cowan and R. Tobin, eds., 24 October
2001. This W3C Recommendation is
http://www.w3.org/TR/2001/REC-xml-infoset-20011024/.
- [RFC2046]
- "Multipurpose
Internet Mail Extensions (MIME) Part Two: Media Types," N.
Freed, N. Borenstein, November 1996.
- [WCAG10]
- "Web Content
Accessibility Guidelines 1.0," W. Chisholm, G. Vanderheiden,
and I. Jacobs, eds., 5 May 1999. This W3C Recommendation is
http://www.w3.org/TR/1999/WAI-WEBCONTENT-19990505/.
- [XML]
- "Extensible Markup
Language (XML) 1.0 (Second Edition)," T. Bray, J. Paoli,
C.M. Sperberg-McQueen, eds., 6 October 2000. This W3C Recommendation is
http://www.w3.org/TR/2000/REC-xml-20001006.
- [AT1998]
- The Assistive Technology
Act of 1998.
- [ATAG10]
- "Authoring Tool
Accessibility Guidelines 1.0," J. Treviranus, C.
McCathieNevile, I. Jacobs, and J. Richards, eds., 3 February 2000. This
W3C Recommendation is
http://www.w3.org/TR/2000/REC-ATAG10-20000203/.
- [ATAG10-TECHS]
- "Techniques
for Authoring Tool Accessibility Guidelines 1.0," J.
Treviranus, C. McCathieNevile, J. Richards, eds., 29 Oct 2002. This W3C
Note is http://www.w3.org/TR/2002/NOTE-ATAG10-TECHS-20021029/.
- [CHARMOD]
- "Character Model
for the World Wide Web," M. Dürst and F. Yergeau, eds., 30
April 2002. This W3C Working Draft is
http://www.w3.org/TR/2002/WD-charmod-20020430/. The latest version is available at
http://www.w3.org/TR/charmod/.
- [DOM2HTML]
- "Document
Object Model (DOM) Level 2 HTML Specification," J. Stenback,
P. Le Hégaret, A. Le Hors, eds., 8 November 2002. This W3C Proposed
Recommendation is
http://www.w3.org/TR/2002/PR-DOM-Level-2-HTML-20021108/. The latest version is
available at http://www.w3.org/TR/DOM-Level-2-HTML/.
- [HTML4]
- "HTML
4.01 Recommendation," D. Raggett, A. Le Hors, and I. Jacobs,
eds., 24 December 1999. This W3C Recommendation is
http://www.w3.org/TR/1999/REC-html401-19991224/.
- [RFC2616]
- "Hypertext
Transfer Protocol — HTTP/1.1," J. Gettys, J. Mogul, H.
Frystyk, L. Masinter, P. Leach, T. Berners-Lee, June 1999.
- [RFC3023]
- "XML Media
Types," M. Murata, S. St. Laurent, D. Kohn, January
2001.
- [SMIL]
- "Synchronized
Multimedia Integration Language (SMIL) 1.0 Specification,"
P. Hoschka, ed., 15 June 1998. This W3C Recommendation is
http://www.w3.org/TR/1998/REC-smil-19980615/.
- [SMIL20]
- "Synchronized
Multimedia Integration Language (SMIL 2.0) Specification,"
J. Ayars, et al., eds., 7 August 2001. This W3C Recommendation is
http://www.w3.org/TR/2001/REC-smil20-20010807/.
- [SVG]
- "Scalable
Vector Graphics (SVG) 1.0 Specification," J. Ferraiolo, ed.,
4 September 2001. This W3C Recommendation is
http://www.w3.org/TR/2001/REC-SVG-20010904/.
- [UAAG10]
- "User Agent
Accessibility Guidelines 1.0," I. Jacobs, J. Gunderson, E. Hansen,
eds.17 December 2002. This W3C Recommendation is available at
http://www.w3.org/TR/2002/REC-UAAG10-20021217/.
- [UAAG10-CHECKLIST]
- An appendix to UAAG 2.0 lists all of the checkpoints, sorted by
priority. The checklist is available in either tabular
form or list
form.
- [UAAG10-ICONS]
- Information about UAAG 1.0 conformance
icons and their usage is available at
http://www.w3.org/WAI/UAAG10-Conformance.
- [UAAG10-SUMMARY]
- An appendix to UAAG 2.0 provides a summary of the goals and structure of User Agent
Accessibility Guidelines 1.0.
- [UAAG10-TECHS]
- "Techniques for
User Agent Accessibility Guidelines 1.0," I. Jacobs, J.
Gunderson, E. Hansen, eds. The latest draft of the techniques document
is available at http://www.w3.org/TR/UAAG10-TECHS/.
- [UNICODE]
- "The
Unicode Standard, Version 3.2." This technical report of the
Unicode Consortium is available
at http://www.unicode.org/reports/tr28/. This is a revision of
"The Unicode Standard, Version 3.0," The Unicode Consortium,
Addison-Wesley Developers Press, 2000. ISBN 0-201-61633-5. Refer also
to http://www.unicode.org/standard/versions/.
For information about character encodings, refer
to Unicode
Technical Report #17 "Character Encoding Model".
- [VOICEBROWSER]
- "Introduction
and Overview of W3C Speech Interface Framework," J. Larson,
4 December 2000. This W3C Working Draft is
http://www.w3.org/TR/2000/WD-voice-intro-20001204/. The latest version is
available at http://www.w3.org/TR/voice-intro/. UAAG 2.0 includes
references to additional W3C specifications about voice browser
technology.
- [W3CPROCESS]
- "World
Wide Web Consortium Process Document," I. Jacobs ed. The 19
July 2001 version of the Process Document is
http://www.w3.org/Consortium/Process-20010719/. The latest version is
available at http://www.w3.org/Consortium/Process/.
- [WCAG20]
- "Web Content Accessibility Guidelines (WCAG) 2.0" B. Caldwell, M. Cooper, L. Guarino Reid, G. Vanderheiden, eds., 8 December 2008. This W3C Recommendation is
http://www.w3.org/TR/2008/REC-WCAG20-20081211/. The latest version is
available at http://www.w3.org/TR/WCAG20/. Additional
format-specific techniques documents are available from this Recommendation.
- [WCAG20-TECHS]
- "Techniques for
Web Content Accessibility Guidelines 2.0," B. Caldwell, M. Cooper, L. Guarino Reid, G. Vanderheiden, eds., 8 December 2008. This W3C Note is
http://www.w3.org/TR/2010/NOTE-WCAG20-TECHS-20101014/. The latest version is
available at http://www.w3.org/TR/WCAG20-TECHS/. Additional
format-specific techniques documents are available from this Note.
- [WEBCHAR]
- "Web
Characterization Terminology and Definitions Sheet," B.
Lavoie, H. F. Nielsen, eds., 24 May 1999. This is a W3C Working Draft
that defines some terms to establish a common understanding about key
Web concepts. This W3C Working Draft is
http://www.w3.org/1999/05/WCA-terms/01.
- [XAG10]
- "XML
Accessibility Guidelines 1.0," D. Dardailler, S. Palmer, C.
McCathieNevile, eds., 3 October 2001. This W3C Working Draft is
http://www.w3.org/TR/2002/WD-xag-20021003. The latest version is available at
http://www.w3.org/TR/xag.
- [XHTML10]
- "XHTML[tm] 1.0:
The Extensible HyperText Markup Language," S. Pemberton, et
al., 26 January 2000. This W3C Recommendation is
http://www.w3.org/TR/2000/REC-xhtml1-20000126/.
- [XMLDSIG]
- "XML-Signature
Syntax and Processing," D. Eastlake, J. Reagle, D. Solo,
eds., 12 February 2002. This W3C Recommendation is
http://www.w3.org/TR/2002/REC-xmldsig-core-20020212/.
- [XMLENC]
- "XML
Encryption Syntax and Processing," D. Eastlake, J. Reagle,
eds., 10 December 2002. This W3C Recommendation is
http://www.w3.org/TR/2002/REC-xmlenc-core-20021210/.
Appendix D:
Acknowledgments
Participants
active in the UAWG prior publication:
- Jim Allan (Co-Chair, Texas School for the Blind and Visually
Impaired)
- Alan Cantor (Invited Expert)
- Bim Egan (Royal National Institute of Blind People)
- Kelly Ford (Co-Chair, Microsoft)
- Mark Hakkinen (Invited Expert)
- Simon Harper (University of Manchester)
- Patrick Lauke (Opera Software)
- Greg Lowney (Invited Expert)
- Kimberly Patch (Invited Expert)
- Jan Richards (Adaptive Technology Resource Centre, University of
Toronto)
- Jeanne Spellman (W3C Staff Contact)
Other
previously active UAWG participants and other contributors to UAAG 2.0:
- Judy Brewer (W3C)
- Sean Hayes (Microsoft)
- Dean Hudson (Apple)
- Cathy Laws (IBM)
- Peter Parente (IBM)
- David Poehlman (Invited Expert)
- Simon Pieters (Opera Software)
- Henny Swan (Opera Software)
- Gregory Rosmaita (Invited Expert)
- David Tseng (Apple)
UAAG 2.0 would not have been possible without the work of those who
contributed to UAAG 1.0.
This publication has been funded in part with Federal funds from the U.S.
Department of Education, National Institute on Disability and Rehabilitation
Research (NIDRR) under contract number ED-OSE-10-C-0067. The content of this
publication does not necessarily reflect the views or policies of the U.S.
Department of Education, nor does mention of trade names, commercial
products, or organizations imply endorsement by the U.S. Government.
Appendix E: Checklist
@@ Editors' Note: This section is still under development@@
Appendix F:
Comparison of UAAG 1.0 guidelines to UAAG 2.0
@@ Editors' Note: This section is still under development@@
Appendix G: Alternative Content
These are the elements and attributes that present 'alternative
content' relevant to Guideline 3.
@@ Editors' Note: This needs update and permanent links as HTML5 goes to rec. Get listings of alternative content for other technologies. Think about better format for presenting it.