2.1.1 Platform Accessibility Architecture: Support a platform accessibility architecture
relevant to the operating environment. (Level A)
- Intent of Success Criterion 2.1.1:
Computers, including many smart phones, have accessibility features built into the operating system. Some well-known APIs for the Windows operating system are: MSAA, iAccessible2, UIAutomation, [more]. Where ever technically possible, support the existing accessibility APIs.
- Examples of Success Criterion 2.1.1 :
- 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 2.1.1:
2.1.2 Name, Role, State, Value,
Description: For all user interface components including user interface, rendered content, generated content, and alternative content, make available the name, role, state, value,
and description via a platform accessibility architecture. (Level A)
- Intent of Success Criterion 2.1.2:
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 2.1.2 :
- 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 legitmate 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 2.1.2:
- @@ Editors' Note: [more needed]
http://msdn.microsoft.com/en-us/library/ms697187
- http://www.mozilla.org/access/windows/msaa-server
2.1.3 Accessible
Alternative: If a component of the user agent user interface cannot be exposed through the platform accessibility architecture, then provide an equivalent alternative that is exposed through the platform accessibility architecture. (Level A)
- Intent of Success Criterion 2.1.3:
Users need to be able to carry out all tasks provided by the user agent. The purpose of this success criterion is to ensure that when circumstances do not allow direct accessibility to some items in the user agent, there is an accessible option that will let them complete their task.
- Examples of Success Criterion 2.1.3 :
- 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 2.1.3:
2.1.4 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 2.1.4:
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 2.1.4 :
- 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 2.1.4:
2.1.5 Write Access: If a User Agent keeps an internal representation of the user content in terms of element structure, relationships between elements, element meaning, or some combination thereof, it must expose this internal representation via an appropriate means (normally by using the platform accessibility architecture or a programmatically available DOM) (level A). 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 2.1.5:
If the user can affect the user interface using any form of input, the same affect may be done through programatic access. It is often more reliable for assistive technology to use the programatic method of access versus attempting to simulate mouse or keyboard input.
- Examples of Success Criterion 2.1.5:
- A volume control slider in a media player can be set directly to the desired value, e.g. the user can speak "Volume 35%".
- A checkbox with a tri-state value, e.g. "checked, unchecked and mixed" where the keystrokes are different to achieve the desired setting, depending on the state. The user can directly select the value when the control is programmatic.
- Related Resources for Success Criterion 2.1.5:
2.1.6 Properties: If any of
the following properties are supported by the accessibility platform
architecture, make the properties available to the accessibility platform
architecture: (Level A)
- the bounding dimensions and coordinates of rendered graphical
objects
- 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
- Intent of Success Criterion 2.1.6:
These properties are all used by assistive technology to allow provide alternative means for the user to view or navigate the content, or to accurately create a view of the user interface and rendered content.
- Examples of Success Criterion 2.1.61:
- 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 2.1.6:
2.1.7 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 2.1.7:
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 2.1.7:
- 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 2.1.7:
- @@ Editors' note: Insert something about performance and classifications.@@
PRINCIPLE 3: Ensure that the user interface
and rendered content are perceivable
Implementing
Guideline 3.1 Provide access to alternative content.
3.1.1 Identify Presence of Alternative Content: The user can have indicators rendered along with rendered elements that have alternative content (e.g. visual icons rendered in proximity of content that has short text alternatives, long descriptions, or captions). (Level A).
- Intent of Success Criterion 3.1.1:
When the author provides alternative content, it is wasted if the user cannot find it. Thus it becomes the responsibility of the user agent to make the presence of alternative content evident to the user. The user 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 3.1.1:
- Distinct visual icons are rendered in proximity of content which has short text alternatives, long descriptions, captions. If the icon forces the text to extend beyond a fixed size container the user agent handles this using its global preference settings to determine whether it expands the container, provides scroll bars, or truncates the content.
- When rendering a Web page using synthesized speech, the browser generates an audible tone to signify the word being read is an acronym, and the user can press the * key to hear the expansion. When the phrase being read is the Alt text for an image, another tone indicates that the user 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 3.1.1:
- (Refer to the SC about handling layout/reflow options.)
3.1.2 Configurable Default
Rendering: The user can globally specify which types of alternative content to render by default. (Level A)
- Intent of Success Criterion 3.1.2:
When the author provides alternative content, it is wasted if the user agent doesn't render it for users who need it. This is a global option because it would be an unreasonable burden for the user to have to change the rendering options every time they visit a new page.
- Examples of Success Criterion 3.1.2:
- In the browser's preferences dialog box, a user specifies that they want 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, a user chooses to always display the alternative ("fallback") content for embedded objects, such as videos.
- The user toggles a menu item which turns on the display of all captions for video and audio content.
- Related Resources for Success Criterion 3.1.2:
3.1.3 Browse and Render:
The user can browse the alternatives, switch between them, and render them 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.
- Intent of Success Criterion 3.1.3:
a. There are times when a user cannot gain meaningful information from a time-based media element. The author may have provided synchronized alternatives for the media. The user 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 3.1.3:
- 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.
Some of the images are graphs. She cannot make sense of the graphs. The author has provided long descriptions for the graphs. Sue toggles the long-discription 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 3.1.3:
- See Success Criterion 2.1.2: Name, Role, State, Value,
Description
3.1.4 Rendering Alternative
(Enhanced): The user can globally configure a
cascade of types of alternatives to render by default, in case a preferred
type is unavailable. If the alternative content has a different height or
width, the user agent will reflow the viewport. (Level AA)
- Intent of Success Criterion 3.1.4:
For a give piece of non-text content the author may have provide 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, audio descriptions in different languages. There may be others. The user is able to 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 3.1.4:
- 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 exit, 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)
- @@ Editors' Note: where do we put the ability for the user to individually pick an image and have the image displayed. It should not have to be an all or nothing. @@
- 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 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 3.1.4:
Implementing
Guideline 3.4 Repair missing content.
3.4.1 Repair Missing
Alternatives: The user has the option
of receiving generated repair text when the user agent recognizes that the author has not provided alternative content required by
the technology specification (e.g.,
short text alternative for an image). (Level A)
- Intent of Success Criterion 3.4.1:
When alternative content is missing, it is sometimes useful for the user
agent to provide alternative information that is available, such as the
filename. The user needs to be able to control the flow of this
information, because it 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.
The user needs to be able 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).
- Examples of Success Criterion 3.4.1:
- 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.
- A video does not have captions. The user selects a caption
button, and the user 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 3.4.1:
3.4.2 Repair Empty
Alternatives: The user has the option
of receiving generated repair text when the user agent recognizes that the
author has provided empty alternative content. (Level AA)
- Intent of Success Criterion 3.4.2:
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 3.4.2:
- 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 3.4.2:
Implementing
Guideline 3.5 Provide highlighting for
selection, content focus, enabled elements, visited links.
3.5.1 Highlighted items:
The user has the option to highlight the following classes of information so that each is uniquely distinguished. (Level A):
- (a) selection,
- (b) content focus,
- (c) recognized
enabled elements, and
- (d) recently visited links.
- Intent of Success Criterion 3.5.1:
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.
- Examples of Success Criterion 3.5.1:
- 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 3.5.1:
- UAAG 3.5.2 Highlighting Options
3.5.2 Highlighting options:
The highlighting options (with the same configurable range as the operating environment's
conventional selection utilities) include at least (Level A):
- (a) foreground colors,
- (b) background colors, and
- (c) input focus (with configurable color
and width).
- Intent of Success Criterion 3.5.2:
A low vision user needs control over what visual properties work best for
highlighting. These include foreground colors, background colors, and
visual borders.
- Examples of Success Criterion 3.5.2:
- 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.
- Related Resources for Success Criterion 3.5.2:
Implementing
Guideline 3.6 Provide text configuration.
3.6.1 Configure Text: The
user can globally set 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, and
- (c) text color (i.e., foreground and
background).
- Intent of Success Criterion 3.6.1:
There are many types of low vision, with different needs for font size, font resolution, and color contrast. Some users want to reduce the font size to decrease the need to scroll the content.
- Examples of Success Criterion 3.6.1:
- Lee has low vision from albinism and has difficulty with screen resolution and brightness. She changes all text to 16 pt Palatino font, with white text on a black background. The serif Palatino font has character spacing that resolves better for her vision. The white on black reduces glare.
- Related Resources for Success Criterion 3.6.1:
3.6.2 Preserve
Distinctions: The user can preserve distinctions in the size of rendered text when that text is rescaled (e.g. headers continue to be larger than body text) within absolute limitations imposed by the platform. (Level A)
- Intent of Success Criterion 3.6.2:
Users who need to enlarge or reduce text should be able to preserve visual cues like proportionally larger headlines so they can easily scan through them.
- Examples of Success Criterion 3.6.2:
- Lee changes all her text to 16 pt Palatino. She needs the headlines to scale proportionally (e.g. 24 pt) in order to preserve headline prominence.
- Related Resources for Success Criterion 3.6.2:
3.6.3 Option Range: The
range of options for each text characteristic includes at least (Level A):
- (a) the range offered by global preference settings supported by the operating environment (i.e. configured though the Control Panel or System) utility,
or
- (b) if no such utility is available,
the range supported by the conventional APIs of
the operating environment for drawing text.
- Intent of Success Criterion 3.6.3:
Users need to be able to access the full range of text characteristics that the operating system supports. The full range may be determined by the operating environment (as determined by the settings). If platform does not provide a range of text characteristics in the control panel, then whatever text characteristics are supported by drawing programs for that operating environment, must be made available to the user.
- Examples of Success Criterion 3.6.3:
- 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 3.6.3:
Implementing
Guideline 3.7 Provide volume configuration.
3.7.1 Global Volume:
The user can globally set volume of all audio tracks it renders (including a "mute" setting) through available operating environment mechanisms. (Level A)
- Intent of Success Criterion 3.7.1:
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 3.7.1:
- 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 3.7.1:
3.7.2 Speech Volume: The user can adjust the volume of all audio tracks the user agent renders, independently or relative to the volume level at the operating environment.
(Level A)
- Intent of Success Criterion 3.7.2:
Users of a screen reader or self voicing browser may encounter content
where the presentation volume of an audio track makes it difficult to
hear the text-to-speech synthesis of their screen reader or browser.
Users should be able to set the individual volume of audio tracks
rendered by the user agent, including text-to-speech synthesis,
independent of the operating environment's volume settings.
- Examples of Success Criterion 3.7.2:
-
A self-voicing user agent provides separate audio volume controls the
speech synthesizer and audio tracks rendered from content. The user
may define default volume levels through a preferences dialog that is
retained across browsing sessions.
- A user encounters a page a video which begins playback on page load
complete. A volume control for rendered audio tracks allows the user
to immediately silence the audio track, while leaving their screen
reader's text-to-speech synthesizer volume at their preferred level. @@ Editors' Note: New examples are needed that are platform specific. @@
- Related Resources for Success Criterion 3.7.2:
Implementing
Guideline 3.8 Provide synthesized speech configuration.
3.8.1 Speech Rate and Volume: The user can set in synthesized speech, overriding any values specified by the author (Level A):
- speech rate and
- speech volume (independently of
other sources of audio).
3.8.2 Speech Pitch and Range: The user can set in synthesized
speech, overriding any values specified by the
author (Level AA):
- (a) pitch ("pitch" refers to the
average frequency of the speaking voice), and
- (b) pitch range ("pitch range"
specifies a variation in average frequency),
3.8.3 Advanced Speech Characteristics: The
user can set all of the speech characteristics offered by the speech
synthesizer, according to the full range of values available, overriding any values specified by the
author. (Level AAA)
- Intent of Success Criterion 3.8.1, 3.8.2, 3.8.3:
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 3.8.1 covers the characteristics that users most commonly need to adjust and that are adjustable in most technologies, while success criterion 3.8.2 covers characteristics that are less widely altered and less widely supported.
- Examples of Success Criterion 3.8.1, 3.8.2, 3.8.3:
- 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.
- @@ Editors' Note: Add an example for 3.8.2 @@
- Related Resources for Success Criterion 3.8.1, 3.8.2, 3.8.3:
3.8.4 Speech Features: The
following speech 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
and one where full number 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 3.8.4:
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 3.8.4:
- The speech synthesizer incorrectly pronounces technical terms employed in the user's organization. These terms are consistently mispronounced in a way that makes it difficult for the audio user 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. The user 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 3.8.4:
Implementing
Guideline 3.9 Provide style sheetsconfiguration.
3.9.1 Author Style Sheets:
If the author has supplied one or more style
sheets, the user has the following options (Level A):
- (a) select a style sheet, or
- (b) turn off style sheets.
3.9.2 User Style Sheets: If
the user has supplied one or more style
sheets, the user has the following options (Level A):
- (a) select a style sheet, or
- (b) turn off style sheets.
- Intent of Success Criterion 3.9.1 & 3.9.2:
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 3.9.1 & 3.9.2:
- 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 3.9.1 & 3.9.2:
Implementing
Guideline 3.10 Help user to use viewports and orient within viewports.
3.10.1 Highlight Viewport:
The viewport with the input focus (including nested viewports and their containers) is highlighted, and the user is able to 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 3.10.1:
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 3.10.1:
- 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 3.10.1:
3.10.2 Move Viewport to Selection and Focus: When a viewport's selection or input focus changes, the viewport moves as
necessary to ensure that the new selection or input focus location is at least partially in the viewport. (Level A)
- Intent of Success Criterion 3.10.2:
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 3.10.2:
- 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 3.10.2:
3.10.3 @@ Editor's Note: Merged with 3.10.2. Renumber @@
3.10.4 Resizable: The user has the option to make graphical viewports
resizable, within the limits of the display, overriding any values
specified by the author. (Level A)
- Intent of Success Criterion 3.10.4:
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 3.10.4:
- 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 3.10.4:
3.10.5 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 3.10.5:
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 3.10.5:
-
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 3.10.5:
3.10.6 Viewport History: If
the user agent maintains a viewport history mechanism (e.g., via the "back
button") that stores previous "viable" states (i.e., that have not been
negated by the content, user agent settings or user agent extensions). It
maintains information about the page and embedded controls, including viewport scrolling, selection and keyboard focus. It restores the saved values when the user returns to a state
in the history. (Level A)
3.10.7 Open on Request: The user has the option of having "top-level"viewports (e.g., windows) only open on explicit user request. In this
mode, instead of opening a viewport automatically, notify the user and allow
the user to open it with an explicit request (e.g., by confirming a prompt or
following a link generated by the user agent). (Level AA)
3.10.8 Do Not Take Focus:
When configured to allow top-level viewports to open without
explicit user request, the user has the option to specify that if a top-level
viewport opens, it does not take the active keyboard focus
. (Level AA)
- Intent of Success Criteria 3.10.6, 3.10.7 & 3.10.8:
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 3.10.6, 3.10.7 & 3.10.8:
-
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 3.10.6, 3.10.7 & 3.10.8:
3.10.9 Stay on Top: The user has the option of having the viewport with the
current focus be displayed and remain on top of all other viewports with which it overlaps.
(Level AA)
- Intent of Success Criterion 3.10.9:
The purpose of this item is to ensure that the active viewport is always available to the user due to the multiple ways the user may be accessing it. Assistive technology for example keys off of the foreground window to report what is happening to the end user.
- Examples of Success Criterion 3.10.9:
- The user agent has multiple viewports to convey the status of what is happening. A file download may be in progress with status displayed in one viewport while a web page is being read in a second. The user wants to determine the file download status so switches to the viewport displaying the file download status. The viewport becomes the topmost window in the user agent.
- Related Resources for Success Criterion 3.10.9:
3.10.10 Close Viewport: The
user can close any top-level viewport. (Level AA)
Note: Dialog boxes or other special purpose viewports that provide limited functionality, do not have to spawn all the user-requested features that do not apply to that special function.
- Intent of Success Criterion 3.10.10:
Put the user in control of what viewports the user agent has opened.
- Examples of Success Criterion 3.10.10:
- A user has multiple viewports open such as from a user agent that supports tabbed browsing and is finished viewing content in one or many of them. The user activates a close button on the viewports that are to be closed and they are closed by the user agent. This reduces distractions from undesired viewports being opened for the user.
- Related Resources for Success Criterion 3.10.10:
3.10.11 Same UI: The user has the option of having all top-level viewports follow the same user interface configuration as the current or
spawning viewport. (Level AA)
- Intent of Success Criterion 3.10.11:
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 3.10.11:
-
An individual using magnification software may know that web content begins one inch from the top of the screen in the user agent and has magnification software configured to present content starting at this location. Offering the ability to have all viewports open with the same user interface means the user can quickly focus on the web content of interest without having to orient to different UI configurations each time a viewport opens.
- Related Resources for Success Criterion 3.10.11:
3.10.12 Indicate Viewport Position:
Indicate the viewport's position relative to rendered
content (e.g., the proportion along an audio or video timeline, the proportion of a Web page before the current position ), and what proportion of the content is currently visible in the viewport along either vertical or horizontal dimension. (Level AAA)
- Intent of Success Criterion 3.10.12:
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 3.10.12:
-
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 3.10.12:
Implementing Guideline 3.11 Provide an effective focus
mechanism.
- Intent of Guideline 3.11
Understanding and controlling focus is key to successful interaction with a user agent and its content. The overall purpose of Guideline 3.11 is to ensure that the user can reliably identify the focus location, and use it to navigate through and manipulate both the content and user interfaces of the user agent, its plug-ins and extensions.
3.11.1 Keyboard Focus: At
least one
keyboard focus is provided for each viewport (including frames), where enabled elements are part of the rendered content. (Level A)
- Intent of Success Criterion 3.11.1:
Users need to be able to tell where the keyboard focus is in order to navigate or manipulate content; without it, a user cannot be sure what effect their next keystroke will have. Cursors are the visual indication of this location, and their locations are also conveyed to assistive technology for users not relying on sight (see success criterion _._._). When the sighted user expects a cursor and does not see one, they can assume that it's in a portion of the content that has scrolled outside the visible portion of the viewport.
- Examples of Success Criterion 3.11.1:
- A user launches a web browser and navigates to a web page. The user starts pressing the tab key and focus begins moving through the links on the webpage.
- Related Resources for Success Criterion 3.11.1:
3.11.2 Current Focus: The
user can make the keyboard focus of each viewport the active input focus. (Level A)
- Intent of Success Criterion 3.11.2:
T
- Examples of Success Criterion 3.11.2:
- Related Resources for Success Criterion 3.11.2:
3.11.3 User Interface Focus:
An active input focus is
provided. (Level A)
- Intent of Success Criterion 3.11.3:
T
- Examples of Success Criterion 3.11.3:
-
A user agent has several menus, toolbars and other controls. As the user presses a key to move to each item on one of the toolbars, the fact that this toolbar item is the active control is made clear through a focus rectangle. When the user switches to a menu, highlighting indicates the active menu element.
- Related Resources for Success Criterion 3.11.3:
3.11.4 Extensions Focusable:
The keyboard focus can navigate within extensions to the user
interface. (Level A)
- Intent of Success Criterion 3.11.4:
T
- Examples of Success Criterion 3.11.4:
- 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 key to move focus to the user interface of this extension and interact with the funtionality offered by the extension. Similarly, the user presses another key to move focus back to the main viewpoert forthe user agent.
- Related Resources for Success Criterion 3.11.4:
3.11.5 Hand-Off Focus: 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 3.11.5:
T
- Examples of Success Criterion 3.11.5:
-
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 3.11.5:
3.11.6 Retrieve Focus: At
any time, the user agent is able to retrieve input focus from a nested viewport
(including nested viewports that are user agents). (Level A)
- Intent of Success Criterion 3.11.6:
T
- Examples of Success Criterion 3.11.6:
- Related Resources for Success Criterion 3.11.6:
3.11.7 Return Focus:
An embedded user agent is responsible for notifying the embedding user
agent that active input focus should move back to it. (Level A)
- Intent of Success Criterion 3.11.7:
T
- Examples of Success Criterion 3.11.7:
- Related Resources for Success Criterion 3.11.7:
3.11.8 Bi-Directional: The
user can move the keyboard focus forward or backward to
any enabled element in the viewport. (Level A)
- Intent of Success Criterion 3.11.8:
T
- Examples of Success Criterion 3.11.8:
- Related Resources for Success Criterion 3.11.8:
3.11.9 Sequential Navigation:
If the author has not specified a navigation order, the default is
sequential navigation, in
document order. (Level A)
- Intent of Success Criterion 3.11.9:
T
- Examples of Success Criterion 3.11.9:
- Related Resources for Success Criterion 3.11.9:
3.11.10 Only on User
Request: The user can specify that the keyboard focus of
a viewport only change on explicit user request. (Level
A)
- Intent of Success Criterion 3.11.10:
T
- Examples of Success Criterion 3.11.10:
- Related Resources for Success Criterion 3.11.10:
3.11.11 On Focus: The user can ensure that moving the keyboard focus to or from an enabled element does not cause the
user agent to take any further action. (Level A)
- Intent of Success Criterion 3.11.11:
T
- Examples of Success Criterion 3.11.11:
- Related Resources for Success Criterion 3.11.11:
Implementing
Guideline 3.12 Provide alternative views.
3.12.1 Text View: For content authored in text formats, a view of the text source is provided. (Level A)
- Intent of Success Criterion 3.12.1:
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 3.12.1:
-
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 3.12.1:
3.12.2 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: What constitutes 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 3.12.2:
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 3.12.2:
-
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 3.12.2:
- This Success Criterion (3.12.2) deals with making document structure
perceivable to the user. It is complimentary to Guideline 4.7 which
deals with making document structure navigable.
3.12.3 Configure Set of Important
Elements:The user can be presented with a hierarchical view of the rendered content that conveys associations implied by author-specified presentation attributes (i.e. position and appearance). (Level AA)
- Intent of Success Criterion 3.12.3:
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 3.12.3:
- Related Resources for Success Criterion 3.12.3:
Implementing
Guideline 3.13 Provide link information.
3.13.1 Basic Link
Information: The following information is provided for each link
(Level A):
- link element content,
- new viewport (whether the author has specified that the resource will open
in a new viewport)
- Intent of Success Criterion 3.13.1:
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 3.13.1:
-
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 3.13.1:
3.13.2 Extended Link
Information: The following information is provided 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 3.13.2:
To be written
- Examples of Success Criterion 3.13.2:
- Related Resources for Success Criterion 3.13.2:
PRINCIPLE 4. Ensure that the user interface is
operable
4.1.1 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 4.1.1:
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 4.1.1 :
- 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 4.1.3)
- 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.
- Related Resources for Success Criterion 4.1.1:
- Microsoft Keyboard accessibility document
- Apple keyboard
- Unix
4.1.2 Keystroke Precedence: The user can specify that keystrokes be processed in the following order:
user agent user interface, user agent extensions, content keystroke
operations administered by the user agent (e.g., access keys, web application controls), and executable
content (e.g., key press events in scripts, etc.). (Level A)
- Intent of Success Criterion 4.1.2:
There are many layers of software that can specify what happens when the user presses a key. For example, the operating system, the user agent interface, the addons or extensions, and author supplied accesskeys or javascript. In addition, the assistive technology the user may be employing will also have assigned key commands. This results in conflicts in order of operations. These conflicts impact user expectations of what will happen when a key is pressed, causing confusion and failure. The most problematic situation is when the author supplied scripting has precedence on the keyboard commands. Therefore, the user needs a preference that a default order: Operating system, user agent interface, addon/extension, accesskeys, javascript.
- Examples of Success Criterion 4.1.2:
- The author codes a script that makes bananas dance on the screen when the user presses Alt-F. The user expectation is that Alt-F will open a file menu. When the bananas dance instead of opening the file menu, the user is confused or blocked from opening the file menu and has no recourse. Therefore, the user agent provides a preference setting that makes the Alt-F open the file menu. There needs to be a toggle ability, so that the user who wants to make the bananas dance can do so.
- Related Resources for Success Criterion 4.1.2:
4.1.3 No Keyboard Trap (Minimum): 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 4.1.3:
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 4.1.3:
- 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.
- Related Resources for Success Criterion 4.1.3:
- Compound documents
- Other SC in UAAG.
4.1.4 Separate Selection from
Activation: 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 4.1.4:
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 4.1.4:
- 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 4.1.4:
4.1.5 Standard Text Area Navigation
Conventions: Views that render text support the standard text area
conventions for the operating environment, including, but not necessarily limited to:
character keys, Backspace/Delete, Insert, arrow key navigation (e.g.,
caret browsing), Page Up/Page Down, navigate to start/end, navigate by
paragraph, shift-to-select mechanism. (Level A)
- Intent of Success Criterion 4.1.5:
Providing a full set of keyboard inputs allows users to efficiently--or at all--perform necessary tasks. Making these inputs consistent within and across programs greatly reduces learning curve, cognitive load, and errors.
- Examples of Success Criterion 4.1.5:
- 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 4.1.5:
4.1.6 Present Direct Commands in Rendered Content: The user can have any recognized direct commands (e.g. accesskey) in rendered content be presented with their associated elements (e.g. "[Ctrl+t]" displayed after a link whose accesskey value is "t", or an audio browser reading the value or label of a form control followed by "accesskey control plus t"). (Level A)
- Intent of Success Criterion 4.1.6:
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.
- Examples of Success Criterion 4.1.6:
- "[Ctrl+t]" displayed after a link whose accesskey value is "t".
- An audio browser reading the value or label of a form control followed by "accesskey control plus t").
- Mnemonic letters in menu titles are shown with an underline. @@ Editors' Note: comment - applicable shortcut indicated or otherwise highlighted@@
- Related Resources for Success Criterion 4.1.6:
4.1.7 Present Direct Commands in User Interface: The user has the option to 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 4.1.7:
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 4.1.7:
- The speech input user who sees a button on a toolbar needs to be able to determine that ctrl+p is the keyboard equivalent for activating the print button. If such key assignments are not displayed as part of the user interface by default, a user agent should have an option to alter UI display to include all direct hotkey assignments visually as part of the controls the hotkeys activate.
- Related Resources for Success Criterion 4.1.7:
4.1.8 Keyboard Navigation:
The user can use the keyboard to navigate from group to group of focusable
items and to traverse forwards and backwards all of the focusable elements within each group. Groups include, but are not limited to, toolbars, panels,
and user agent extensions. (Level AA)
- Intent of Success Criterion 4.1.8:
Let the user navigate between sections without having to sequentially navigate through everything in every section. Efficient keyboard navigation is especially important for people who cannot easily use a mouse.
- Examples of Success Criterion 4.1.8:
- Ctrl+Tab moves the focus to the first navigable item in the next frame.
- The Tab key moves the focus to or away from a group of radio buttons, and then directional keys move between buttons within that group.
- Related Resources for Success Criterion 4.1.8:
4.1.9 Important Command Functions: Important command functions (e.g. related to navigation, display, content, information management) are available using a single or sequence of keystrokes or key combinations. (Level AA)
- Intent of Success Criterion 4.1.9:
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 4.1.9:
- 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.
- Related Resources for Success Criterion 4.1.9:
- Links to 1.1. Comply with applicable
specifications and conventions
4.1.10 Override of UI Keyboard Commands:
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 4.1.10:
Users need to be in control of how they interact with the user agent. Assistive technology and physical keyboard input needs mean that certain keyboard combinations are easier for a user to enter.
- Examples of Success Criterion 4.1.10:
- 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.
- @@ Editors' Note: another example - one handed keyboardist needs to map all keys to the left side of the keyboard @@
- Related Resources for Success Criterion 4.1.10:
4.1.11 User Override of Accesskeys: The
user can override any recognized author supplied content keybinding (i.e. access key). The user must have an option to save the
override of user interface keyboard shortcuts so that the rebinding persists
beyond the current session. (Level AA)
- Intent of Success Criterion 4.1.11
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 4.1.11:
- A speech recognition user has defined standard commands to access commonly used parts of a Web site. For example, speaking the 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 4.1.11:
4.1.12 Specify preferred keystrokes: 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. access to help). (Level
AA)
- Intent of Success Criterion 4.1.12
N/A
- Examples of Success Criterion 4.1.12:
- Related Resources for Success Criterion 4.1.12:
4.2.1 List event handlers: The user can, through keyboard input alone, call up a list of input device event handlers explicitly associated with the keyboard focus element. (Level A)
- Intent of Success Criterion 4.2.1:
Users interacting with a web browser may be doing so by voice, keyboard, mouse or another input technology or a combination of any of these. No matter how the user is controlling the user agent, he or she need to know all the input methods assigned to a particular piece of content.
- Examples of Success Criterion 4.2.1:
- A user may tab to a link that has a flyout menu that appears OnMouseOver. The User agent needs to notify the user of this menu so he or she can know the menu is available. Other success criteria ensure the keyboard user here can interact with this menu.
- Related Resources for Success Criterion 4.2.1:
4.2.2 Activate any event handler: The
user can, through keyboard input alone, activate any
input device event handlers explicitly
associated with the
keyboard focus element. (Level A)
- Intent of Success Criterion 4.2.2:
Although it should not do so, some Web content is designed to work only with certain input devices, such as a mouse, and make functionality available only through event handlers for those devices. Some users interacting with a web browser may be doing so by voice, keyboard, mouse or another input technology or a combination of any of these. No matter how the user is controlling the user agent, he or she must be able to activate any of the event handlers regardless of the interaction technology being used.
- Examples of Success Criterion 4.2.2 :
- A user who cannot use a mouse needs to activate a flyout menu that normally appears OnMouseOver. The user should be able to navigate to a link and activate it using keyboard shortcuts.
- Related Resources for Success Criterion 4.2.2:
4.2.3 Activate all event handlers: The user can, through keyboard input alone, simultaneously activate all input device event handlers explicitly associated with the
content focus element. (Level A)
- Intent of Success Criterion 4.2.3:
One input method should not hold back another. 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 4.2.3:
- Speech input users may combine moving the mouse up, left and clicking in a single command phrase.
- A link has an onmousedown and an onmouseup event link. The keyboard user can use 1 key click to activate both events.
- Related Resources for Success Criterion 4.2.3:
4.3.1 Timing Adjustable:
Where time limits for user input are recognized
and controllable by the user agent, the user can extend the time
limit. (Level A)
- Intent of Success Criterion 4.3.1:
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 4.3.1:
- 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 4.3.1:
Implementing Guideline 4.4 Help users avoid flashing that could cause seizures.
[Return to Guideline]
4.4.1 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 4.4.1:
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 4.4.1:
- 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 4.4.1:
4.4.2 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 4.4.2:
- Examples of Success Criterion 4.4.2:
- Related Resources for Success Criterion 4.4.2:
Guideline
4.5 Configure and store preference settings.
4.5.1 Change Preference Settings The user can change settings that impact accessibility. (Level A)
4.5.2 Persistent Accessibility Settings: User agent accessibility preference settings persist between sessions. (Level A)
4.5.3 Multiple Sets of Preference Settings: The
user can save and retrieve multiple sets of user agent preference settings.
(Level AA)
4.5.4 Portable Preference Settings:The user can transfer preference settings across locations onto a compatible system. (Level AAA)
4.5.5 Preferences Wizard: A
wizard helps the user to configure the accessibility-related
user agent preferences (at least). (Level AAA)
4.5.6 Restore all to default: The user can restore all preference settings to default values. (Level A)
4.5.7 Restore related preferences to default: The user can restore groups of related preference settings to default values (e.g. reset keyboard shortcuts, reset colors and sizes of rendered content). (Level AA)
4.5.8 Change preference setting outside the UI: The user can adjust preference settings from outside the user agent user interface. (Level AA)
- Intent of Success Criterion 4.5:
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 4.5:
- 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 4.5:
- SCORM Editors' Note: (Jutta's work) - find current reference @@
4.6.1 Find: The user can perform a search within rendered content (e.g., not hidden with a style), including text alternatives, for any sequence of characters from the document character set set. (Level A)
- Intent of Success Criterion 4.6.1:
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 4.6.1:
- 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 4.6.1:
4.6.2 Find Direction: The user can search forward or backward from the focused location in content. The user is notified of changes in search direction. The user is notified when the search reaches the upper or lower extent of the content based on the search direction. (Level A)
- Intent of Success Criterion 4.6.2:
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 4.6.2:
- 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 4.6.2:
4.6.3 Match Found: When there is a match, the user is alerted and the viewport moves so that the matched text content is at least partially within it. The user can search for the next instance of the text from the location of the match.
- Intent of Success Criterion 4.6.3:
@@ Editors' Note: If the caret has been moved, from its new location.@@ (Level A)
- Examples of Success Criterion 4.6.3:
- Related Resources for Success Criterion 4.6.3:
4.6.4 Alert on No Match: The user is
notified when there is no match or after the last match in content (i.e.,
prior to starting the search over from the beginning of content). (Level
A)
- Intent of Success Criterion 4.6.4:
Not yet drafted
- Examples of Success Criterion 4.6.4:
- Related Resources for Success Criterion 4.6.4:
4.6.5 Advanced Find: The user agent provides an accessible advanced
search facility, with a case-sensitive and case-insensitive search
option, and the ability for the user to perform a search within all
content (including hidden content and captioning) for text and text
alternatives, for any sequence of characters from the document character
set. (Level AA)
- Intent of Success Criterion 4.6.5:
Not yet drafted
- Examples of Success Criterion 4.6.5:
- Related Resources for Success Criterion 4.6.5:
4.7.1 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 4.7.1:
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 4.7.1:
- 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 4.7.1:
- See 4.1.4 for discussion of letting the user configure the list of important elements to suit their task.
4.7.2 Direct navigation: The user can navigate directly to important (structural and
operable) elements in rendered content. (Level A).
- Intent of Success Criterion 4.7.2:
Not yet drafted
- Examples of Success Criterion 4.7.2:
- Related Resources for Success Criterion 4.7.2:
4.7.3 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 4.7.3:
@@ Editors' Note: postponed for more information about the intent of this SC. Is it
about providing flyover information? Or is it out of place and really
belongs in Principle 2? @@
- Examples of Success Criterion 4.7.3 :
- Related Resources for Success Criterion 4.7.3 :
- also see Success Criteria 4.7.x Location in Hierarchy
4.7.4 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 4.7.4 :
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 4.7.4 :
- 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 4.7.4 :
@@ Editors' Note: Success Criteria from 3.3 have been
moved to 4.9. SC 3.3.3 has been moved to 5.1@@
4.7.5 Direct activation: The user can move directly to and activate any operable
elements in rendered content. (Level AA)
- Intent of Success Criterion 4.7.5:
Not yet drafted
- Examples of Success Criterion 4.7.5:
- Related Resources for Success Criterion 4.7.5:
4.7.6 Configure Set of Important Elements: The user has the option to
configure the set of important elements for structured navigation, including
by element type (e.g., headers, list items, images). (Level AAA) @@ Editor's
note: Review the definition of "important elements" @@
- Intent of Success Criterion 4.7.6:
Not yet drafted
- Examples of Success Criterion 4.7.6:
- Related Resources for Success Criterion 4.7.6:
4.7.7 Discover navigation and activation keystrokes: Direct navigation and activation keystrokes are discoverable both
programmatically and via perceivable labels. (Level A)
- Intent of Success Criterion 4.7.7:
Not yet drafted
- Examples of Success Criterion 4.7.7:
- Related Resources for Success Criterion 4.7.7:
@@ Editor's note: Review the definition of "important elements" @@
Guideline 4.8 Provide toolbar
configuration.
4.8.1 Configure Position:
When graphical user agent user interfaces
have toolbars, the user can add, remove and configure the
position of user agent user interface
controls on those toolbars from a pre-defined set of controls. (Level
AAA)
- Intent of Success Criterion 4.8.1:
Not yet drafted
- Examples of Success Criterion 4.8.1:
- Related Resources for Success Criterion 4.8.1:
4.8.2 Restore Default Toolbars: The
user can restore the default toolbar configuration. (Level AAA)
- Intent of Success Criterion 4.8.2:
Not yet drafted
- Examples of Success Criterion 4.8.2:
- Related Resources for Success Criterion 4.8.2:
Guideline 4.9 Provide control of
content that may reduce accessibility.
4.9.1 Background Image
Toggle: The user has the global option
to hide/show background images. (Level
A)
4.9.2 Time-Based Media
Load-Only: The user can
load time-based media content @@ Editors' Note: DEFINE@@
such that the first frame is displayed (if video), but the content is not
played until explicit user request. (Level
A)
4.9.3 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)
4.9.4 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)
4.9.5 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%).
4.9.6 Stop/Pause/Resume
Multimedia: The user can stop, pause, and resume rendered audio and
animation content (including video and
animated images) that last three or more seconds at their default playback
rate. (Level A)
- Intent of Success Criterion 4.9.6:
Not yet drafted
- Examples of Success Criterion 4.9.6:
- Related Resources for Success Criterion 4.9.6:
4.9.6 Navigate Multimedia: 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 4.9.6:
Not yet drafted
- Examples of Success Criterion 4.9.6:
- Related Resources for Success Criterion 4.9.6:
4.9.7 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 (AA).
- Intent of Success Criterion 4.9.7:
Not yet drafted
- Examples of Success Criterion 4.9.7:
- Related Resources for Success Criterion 4.9.7:
4.9.8 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. These selections may override global default settings for captions, audio descriptions, etc.
- Intent of Success Criterion 4.9.8:
Not yet drafted
- Examples of Success Criterion 4.9.8:
- Related Resources for Success Criterion 4.9.8:
4.9.9 Sizing Playback Viewport: User can adjust the size of the time-based media up to the full height or width of the containing viewport. In doing so, the user can preserve aspect ratio and to adjust the size of the playback viewport to avoid cropping, within the scaling limitations imposed by the media itself. (Level AA)
- Intent of Success Criterion 4.9.9:
User needs video larger but still needs access to other application (take notes during playback), fullscreen does not allow that. Content should reflow as user adjusts playback viewport.
- Examples of Success Criterion 4.9.9:
- Related Resources for Success Criterion 4.9.9:
4.9.10 Scale and position alternative media tracks: User can scale and position alternative media tracks independent of base video. (Level AAA)
- Intent of Success Criterion 4.9.10:
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 4.9.10:
- To be written @@ Editors' Note: University of Toronto had working examples 10 years ago. Geoff Freed and Larry Goldberg session at CSUN 2 years ago showed many examples caption in different locations, but not the user could disconnect and move where needed.@@
- Related Resources for Success Criterion 4.9.10:
4.9.11 Adjust Playback Contrast and Brightness: User can control the contrast and brightness of the content within the playback viewport.
- Intent of Success Criterion 4.9.11:
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 4.9.11:
- Related Resources for Success Criterion 4.9.11:
Applicability Notes:
The guideline only applies to images, animations, video, audio, etc. that
the user agent can recognize.
@@ Editors' Note: If the browser is playing the video natively, there is only 1 user agent. In that case, it falls on the browser to meet the UAAG spec. @@
@@ Editors' Note: If an author uses windows media player inside the video element, the browser needs to map its native controls to the embedded wmp controls, and provide access to all the controls. @@
@@ Editors' Note: User needs to be able to define rendering parameters of playback at render-time. @@
Principle 5: Ensure that the user interface is
understandable
Implementing Guideline 5.1 Help users avoid
unnecessary messages.
[Return to Guideline]
5.1.1 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 (e.g., ignoring updating content
marked "polite" ). (Level AA)
- Intent of Success Criterion 5.1.1:
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 5.1.1:
- 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.
- Related Resources for Success Criterion 5.1.1:
5.1.2 Retrieval Progress:
Show the progress of content retrieval. (Level A)
- Intent of Success Criterion 5.1.2 :
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 5.1.2 :
- 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 5.1.2:
Guideline 5.2 Help users avoid and correct
mistakes.
5.2.1 Form Submission: The user can redefine keyboard shortcuts for submitting and canceling recognized forms. (Level AA)
- Intent of Success Criterion 5.2.1:
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 5.2.1:
-
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 5.2.1:
Guideline 5.3 Document the user agent user
interface including all accessibility features.
5.3.1 Accessible documentation:
The product documentation is available in a format that conforms to WCAG 2.0 Level "A" or greater.
- Intent of Success Criterion 5.3.1:
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 5.3.1:
-
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 5.3.1:
5.3.2 Document Accessibility
Features: All user agent features
that benefit accessibility @@ Editors' Note: DEFINE - as specified
in the conformance claim@@ are documented. (Level A)
- Intent of Success Criterion 5.3.2:
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 5.3.2:
-
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.
- Related Resources for Success Criterion 5.3.2:
5.3.3 Changes Between
Versions: Changes to features that
affect accessibility since the previous version of the user agent are
documented. (Level AA)
- Intent of Success Criterion 5.3.3:
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 5.3.3:
- Sample text: "In this version, we added the ability to display tooltips on elements with a title attribute when using the keyboard. With caret browsing turned on simply arrowing onto an element with a title the tooltip will remain visible while the caret is within the element."
- Related Resources for Success Criterion 5.3.3:
5.3.4 Centralized
View: There is a centralized view
of all features of the user agent that benefit accessibility, in a dedicated
section of the documentation. (Level AA)
- Intent of Success Criterion 5.3.4:
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 (eg. 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 5.3.4:
- 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 5.3.4:
5.3.5 Context Sensitive
Help: There is context-sensitive
help on all user agent features that benefit accessibility. (Level AAA)
- Intent of Success Criterion 5.3.5:
The purpose of this criteria is to help maximize the discovery of user agent features that benefit accessibility.
- Examples of Success Criterion 5.3.5:
- 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 5.3.5:
5.3.6 Appropriate Language: If characteristics of the user agent involve producing an end user experience such as speech, the user agent reacts appropriately to language changes.
- Intent of Success Criterion 5.3.6:
The goal of this criteria is to ensure that user agents present spoken web content with in the language appropriate to the content as indicated by the lang attribute. Authors use this tag to indicate the language of content.
- Examples of Success Criterion 5.3.6:
- A user agent has a feature to read web pages verbally using synthetic speech. A user is browsing a web site devoted to language translation. As the browser is speaking the content of the page, the synthetic speech switches to the language of the content, using appropriate pronunciation and related characteristic's for the language.
- Related Resources for Success Criterion 5.3.6:
5.4 The user agent must behave in a predictable fashion.
5.4.1 Control default focus: The user agent provides a mechanism for setting global configuration of default focus.
- Intent of Success Criterion 5.4.1:
Users need to know that navigation in a web page is going to start in a predictable location. While we recognize that it may be desirable for accessibility to set focus to specific link on a page other than the first link, the user needs to be in control of this feature.
- Examples of Success Criterion 5.4.1:
- Example: the page has a default focus to search box, the user has to take additional scrolling to get to the content that was not in the search box. The user may want to set their page so it starts at the first link, not the search box.
- Related Resources for Success Criterion 5.4.1:
5.4.2 Unpredictable focus: The user is informed when the user agent changes focus. The user agent provides a global option to block uninitiated focus changes.
- Intent of Success Criterion 5.4.2:
Not yet drafted
- Examples of Success Criterion 5.4.2:
- A speech user issues a command to execute at a specific location, and the focus changes without the user's control, so the command fails or executes with unpredictable results.
- Moving the focus in an form, where the field advances without the user hitting tab, and the user hits tab (telephone number fields) so that the focus moves to the next field. It can give an error message that the skipped field is left blank.
- Related Resources for Success Criterion 5.4.2:
@@ Editors' Note: Missing: Greater ease in interpreting security messaging. Should be cross-referenced with the security working group. @@
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.
In order for a Web page to conform to UAAG 2.0, one of the following levels of conformance is met
in full.
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.
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):
A description of how the UAAG 2.0 success criteria were met where this
may not be obvious.
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.
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 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 ED05CO0039. 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.