This document provides supporting information for the User Agent Accessibility Guidelines (UAAG)
2.0 for designing user agents that lower
barriers to Web accessibility for people with disabilities. User agents include
browsers and other types of software that retrieve and render Web content. A user agent that conforms to these guidelines will promote accessibility
through its own user interface and through other internal facilities, including
its ability to communicate with other technologies (especially assistive technologies).
Furthermore, all users, not just users with disabilities, should find
conforming user agents to be more usable. In addition to helping developers of
browsers and media players, this document will also benefit developers of
assistive technologies because it explains what types of information and
control an assistive technology may expect from a conforming user agent.
Technologies not addressed directly by UAAG 2.0 (e.g., technologies for braille
rendering) will be essential to ensuring Web access for some users with
This document provides explanation of the intent of UAAG 2.0 success
criteria, examples of implementation of the guidelines, best practice
recommendations and additional resources for the guideline.
The "User Agent Accessibility Guidelines 2.0" (UAAG 2.0) is part of
a series of accessibility guidelines published by the W3C Web Accessibility
This section describes the status of this document at the time of its
publication. Other documents may supersede this document. A list of current
W3C publications and
the latest revision of this technical report can be found in the W3C technical reports index
Editor's Draft of UAAG
This document is the internal working draft used by the UAWG and is updated continuously and
without notice. This document has no formal standing within W3C. Please consult
the group's home page and the W3C technical reports index for information
about the latest publications by this group.
Web Accessibility Initiative
This document has been produced as part of the W3C Web Accessibility Initiative (WAI). The goals
of the User Agent Working Group (UAWG) are discussed in the Working Group charter. The
UAWG is part of the WAI Technical Activity.
Publication as a Working Draft does not imply endorsement by the W3C Membership. This is a draft
document and may be updated, replaced or obsoleted by other documents at any
time. It is inappropriate to cite this document as other than work in progress.
This document was produced by a group operating under the 5 February 2004 W3C
Patent Policy. The group does not expect this document to become a W3C
Recommendation. W3C maintains a public list of any patent
disclosures made in connection with the deliverables of the group; that
page also includes instructions for disclosing a patent. An individual who has
actual knowledge of a patent which the individual believes contains Essential
Claim(s) must disclose the information in accordance with section
6 of the W3C Patent Policy.
A user agent is any software that retrieves, renders and facilitates
end-user interaction with Web content.
as a User Agent?
The following tests can be used to determine if software qualifies as a user
agent for the purposes of these guidelines. It divides potential user agents
into Primary Agents (the traditional "browser"), Extensions and Plug-ins, and
Web-based User Agents.
If the following three conditions are met then it is a Primary User Agent
and Must Conform to UAAG:
- If it is a standalone application; and
- If it interprets any w3c specified language; and
- If it provides a user interface or interprets either a procedural or
declarative language that may be used to provide a user interface.
If the following two conditions are met then it is a User Agent Extension or
Plug-In and Must Conform to UAAG:
- If it is launched by, or extends the functionality of, a Primary User
- If post-launch user interaction either becomes part of, or is within the
bounds of, the Primary User Agent.
If the following three conditions are met then it is a Web-Based User Agent and
Must Conform to UAAG:
- If the user interface is generated by the interpretation of either a
procedural or declarative language; and
- If this interpretation is by a Primary User Agent, User Agent Extension
or Plug-In; and
- If user interaction is not passed to and from the Primary User Agent,
User Agent Extension or Plug-In, or if user interaction does not modify the
Document Object Model of its containing document.
UAAG 2.0 Guidelines
PRINCIPLE 1: Comply with applicable
specifications and conventions
Guideline 1.1 Ensure that non-Web-based functionality is accessible. [Return to
Accessible (Level A): Non-Web-based user agent user interfaces comply
with and cite the "Level A" requirements of
standards or operating environment conventions
that benefit accessibility. The "Level A" requirements
are those that are functionally equivalent to WCAG Level A success criteria.
- Intent of Success Criterion 1.1.1:
The user should be able to easily discover detailed information about the
user agent's adherence to accessibility standards of the operating
environment or adherence to external accessibility requirements without
installing and testing the accessibility features.
- Examples of Success Criterion 1.1.1 :
- User agent X lists the platform accessibility tools (high contrast,
show sounds, sticky keys, etc) supported. Additionally, the user agent
lists all of the platform accessibility APIs or other APIs that are
supported. "Google Chrome supports the Windows Accessibility API (MSAA)
to display accessibility information and events for its features and
web content. http://www.google.com/support/chrome/bin/answer.py?hl=en&answer=96831"
- Related Resources for Success Criterion 1.1.1:
Accessible (Level AA): Non-Web-based user agent user interfaces comply
with and cite the "Level AA" requirements of standards or operating environment conventions
that benefit accessibility. The "Level AA" requirements are those that are
functionally equivalent to WCAG Level AA success criteria. (Level AA)
Accessible (Level AAA): Non-Web-based user agent user interfaces
comply with and cite the "Level AAA" requirements of standards or operating environment conventions
that benefit accessibility. The "Level AAA" requirements are those that are
functionally equivalent to WCAG Level AAA success criteria. (Level AAA)
This guideline does not apply to Web-based user agent user interfaces, but
does include any parts of Web-based user agents that are non-Web-based @@ Editors' Note: DEFINE@@ (e.g., client-side file
Guideline 1.2 Ensure that Web-based functionality is accessible. [Return to
Accessible (Level A): User agent user interfaces that are rendered
using Web standard technologies conform to WCAG Level "A". (Level A)
- Intent of Success Criterion 1.2.1:
Not yet drafted
- Examples of Success Criterion 1.2.1 :
- Related Resources for Success Criterion 1.2.1:
Accessible (Level AA): User agent user interfaces that are rendered
using Web standard technologies conform to WCAG Level "AA". (Level AA)
- Intent of Success Criterion 1.2.2:
Not yet drafted
- Examples of Success Criterion 1.2.2 :
- Related Resources for Success Criterion 1.2.2:
Accessible (Level AAA): User agent user interfaces that are rendered
using Web standard technologies conform to WCAG Level "AAA". (Level AAA)
- Intent of Success Criterion 1.2.3:
Not yet drafted
- Examples of Success Criterion 1.2.3 :
- Related Resources for Success Criterion 1.2.3:
This guideline does not apply to non-Web-based user agent user interfaces,
but does include any parts of non-Web-based user agents that are Web-based
(e.g., help systems).
Features: Implement and cite in the conformance claim the
accessibility features of content and
specifications. Accessibility features are those that are either (Level A):
- identified as such in the specification or
- allow authors to satisfy a requirement of WCAG.
- Intent of Success Criterion 1.3.1:
- @@ Editors' Note: add a sentence about the
importance of content standards @@
If browsers and players don't seamlessly conform to platform accessibility
features, then users can't easily take advantage of those features.
Software that has versions for different platforms, may have to handle
accessibility differently on different platforms or operating systems. In
order to show that you have implemented the accessibility features of the
platform correctly, these features are identified in the conformance
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 1.3.1 :
- If you are developing for the Gnome platform,
consult the Gnome Accessibility Developers Guide. For example, the
Keyboard Focus [link:
section states: "Show current input focus clearly at all times.
Remember that in controls that include a scrolling element, it is not
always sufficient to highlight just the selected element inside that
scrolling area, as it may not be visible. " If your program controls
focus, make sure you conform to this accessibility guideline for focus.
In the conformance claim [link to conformance section], list the
requirements you fully comply with, list the requirements you partially
comply with and explain, and list the requirements you do not comply
with and explain. Where applicable, this explanations can be general
and cover several sections at once.
- Related Resources for Success Criterion 1.3.1:
- 5.3.2 Document Accessibility
to Accessibility Overview," Apple Computer Inc.
to Accessibility Programming Guidelines for Carbon," Apple
to Accessibility Programming Guidelines for Cocoa," Apple
Desktop Software standards," Electronic Information Technology
Access Advisory (EITAAC) Committee.
Accessibility for Developers," C. Benson, B. Cameron, B. Haneman,
S. Snider, P. O'Briain, The GNOME Accessibility Project.
Accessibility Toolkit API"
Keyboard Shortcuts," Novell Corporation.
Accessibility," IBM Special Needs Systems.
- IEC/4WD 61966-2-1: Colour Measurement and
Management in Multimedia Systems and Equipment - Part 2.1: Default
Colour Space - sRGB. May 5, 1998.
of human-system interaction -- Guidance on accessibility for
human-computer interfaces". International Organization for
Guidelines for Writing Accessible Applications Using 100% Pure
Java," R. Schwerdtfeger, IBM Special Needs Systems.
Accessibility Guidelines and Checklist," IBM Special Needs
- "Mac OS X keyboard
shortcuts," Apple Corporation.
for Applications Designers," Microsoft Corporation.
Software For Accessibility", Microsoft Corporation.
shortcuts for Windows," Microsoft Corporation.
Notes application accessibility," IBM Corporation.
- "Designing for
Accessibility," Eric Bergman and Earl Johnson. This paper
discusses specific disabilities including those related to hearing,
vision, and cognitive function.
- [Editors' Note: Resource links from Jim -
compare and expand]
Specifications: Render content according to the technology specification. This includes
any accessibility features of the technology (see Guideline 1.3). (Level A)
- Intent of Success Criterion 1.4.1:
End users and assistive technology products
assume that content will be rendered in a predictable fashion. This success
criterion ensures that user agents provide this level of predictability.
Note: It may be necessary to
ignore aspects of the technology specification where they would actually
harm, rather than improve, overall accessibility. In these cases user agent
developers are encouraged to deviate from those aspects of the standard,
and document the decision in their conformance claim. For example, the CSS
spec says generated content should not appear in the DOM, which may mean
that generated content would not be exposed to assistive technology and
thus may not be accessible to blind users. User agents should instead
expose the generated content through the DOM, and document their decision
to ignore that aspect of the specification.
- Examples of Success Criterion 1.4.1 :
- A user agent implements the WAI-ARIA
(Accessible Rich Internet Applications) standard, and the developer
follows the "Implementing ARIA" document by mapping ARIA roles and
events to the supported platform accessibility infrastructure (MSAA,
UIA, ____, etc.). This allows a screen reader that supports the
platform infrastructure to correctly support ARIA in the user
- An organization creates an optional style sheet
that enlarges fonts and adapts all colors for maximum contrast. They
can be confident that when their Web site uses this style sheet it will
work with any browser because those browsers have implemented CSS
according to the CSS specification.
- Related Resources for Success Criterion 1.4.1:
1.4.2 Handle Unrendered
Technologies: If the user agent does not
render a technology, it allows the user to choose a way to handle content in
that technology (e.g., by launching another application or by saving it to
disk). (Level A)
- Intent of Success Criterion 1.4.2:
Users who have disabilities may have fewer
options in terms of how they access the information. Information is made
available in a variety of fashions on the Internet, and at times a specific
format may be the only way in which information is available. If the user
agent cannot render that format it needs to let the user access that
content through alternate means, such as invoking a third-party renderer or
saving the file to the user's hard drive.
- Examples of Success Criterion 1.4.2 :
- Tracy has low vision and finds it much more
convenient to access her bank statement electronically than on paper,
even though the electronic version is in a TIFF image, a format that
her browser cannot render. In this case, the browser lets her save the
image to her hard drive so she can open it in another program.
- Related Resources for Success Criterion 1.4.2
1.4.3 Alternative content
handlers: The user has the ability to select content elements and
have them rendered in alternative viewers. (Level AA)
- Intent of Success Criterion 1.4.3:
When accessing media content on the Web, users
with disabilities sometimes find they have a richer or more accessible
experience in a third-party application than using their browser's build-in
facilities. In these cases they want to be able to navigate to content in
their browser, then save that content to their disk or launch it in a
- Examples of Success Criterion 1.4.3 :
- A browser supports the VIDEO tag and adds its
own play and pause controls, but George prefers to view the video
content in a third-party application that provides much more
sophisticated navigation controls such as bookmarks, skip-forward and
backwards, and the ability to speed playback without increasing pitch
of the audio track. In the browser, he right-clicks on the video to
display a context menu, and from that chooses "Open in…", and then
chooses his preferred video player. The browser launches the player to
show that video file in the browser's cache folder. The browser saves
the video to a temporary location on the user's disks (or uses one
already in its cache folder), then launches the player to show that
In the case of streaming video that cannot be saved to disk, the
browser launches the external viewer passing it the URL to the online
- Related Resources for Success Criterion 1.4.3
When a rendering requirement of another specification contradicts a
requirement of UAAG 2.0, the user agent may disregard the rendering requirement
of the other specification and still satisfy this guideline.
PRINCIPLE 2: Facilitate programmatic access
Implementing Guideline 2.1 Facilitate programmatic access [Return to
- Intent of Success Criterion 2.1.1:
Computers, including many smart phones, have accessibility features and
support for Assistive Technologies built into the operating system.
Assistive technologies often use a combination of methods to get
information about, and manipulate, a user agent's user interface and the
content it's rendering. These methods include DOMs, accessibility APIs such
as MSAA or JAA, general-purpose platform APIs such as those used to
determine a window's title, application-specific APIs that that are
typically a last resort when an application does not make all information
available through the former means, and hard-coded heuristics. It is the
user agent's responsibility to make the necessary information and
facilities available through the appropriate corresponding means. Platform
accessibility API is particularly important because it provides common
functionality across all (or at least all well behaved) applications
running on the platform, reducing the amount of special-casing the
assistive technology has to implement for each of the hundreds of
applications it supports.
- Examples of Success Criterion 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.
- Intent of Success Criterion 2.1.2:
The information that assistive technology
requires is the
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.
- Name (component name)
- Role (purpose, such as alert, button, checkbox,
- State (current status, such as busy, disabled,
- 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
- 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=
@@ 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
The slider’s current value.
The minimum of the value range
The maximum of the value range
aria-describedby = 'Use the right or left arrow key to change the sound
- Related Resources for Success Criterion 2.1.2:
- @@ Editors' Note: [more needed]
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 who rely on assistive technology need to be able to carry out all
tasks provided by the user agent, just like everyone else. When a
particular user interface component cannot support for the platform
accessibiltiy architecture, and thus can't be made compatible with
assistive technology, the user agent should let the user achieve the same
goal using another component that IS fully accessible.
- Examples of Success Criterion 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
Availability of DOMs: If the user agent implements one or more DOMs,
they must be made programmatically available to assistive technologies. (Level
- 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
- 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:
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:
- When the user says the phrase 'Volume 35%' their speech input utility
can programmatically set the value of the volume slider to 35%, rather
than having to use trial and error by simulating mouse clicks or arrow
presses to try to find the 35% point.
- "Francois directs his third-party macro utility to set the value of a
tri-state check box to "mixed". Even though the control would normally
need to be cycled through its states of “on”, “off”, and
“mixed”, the macro utility can set the control directly to the
- Related Resources for Success Criterion 2.1.5:
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
- 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
- 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:
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
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
- 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
- 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.)
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
- In the browser's preferences dialog box, a user chooses to always
display the alternative ("fallback") content for embedded objects, such
- 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
- 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
- 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
- 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,
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
- 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
- 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
- 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,
- Related Resources for Success Criterion 3.4.2:
Guideline 3.5 Provide highlighting for selection, content focus,
enabled elements, visited links.
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
- 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
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
- 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
- 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
- Related Resources for Success Criterion 3.5.2:
Implementing Guideline 3.6 Provide text
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
- (b) font family, and
- (c) text color (i.e., foreground and
- 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
- 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:
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:
The relative size of text provides visual cues that help in understanding
and navigating web content. For example, headlines in a larger font than
the body text. Users who set preferences to enlarge or reduce the text size
need to have these visual cues preserved.
- Examples of Success Criterion 3.6.2:
Lee finds text easiest to read at 16 pt Palatino, so chooses to have her
browser display all text in the Palatino font of at least 16 pt in size.
She needs the headlines to scale proportionally (e.g. 24 pt) in order to
preserve headline prominence.
- Related Resources for Success Criterion 3.6.2:
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
- 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
- Related Resources for Success Criterion 3.6.3:
Implementing Guideline 3.7 Provide volume
Volume: The user can globally set volume of all audio tracks it renders (including a "mute"
setting) through available operating environment mechanisms.
- 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:
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
- 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
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.
- 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,
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
- (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
- 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
- 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:
Guideline 3.9 Provide style sheetsconfiguration.
- (a) select a style sheet, or
- (b) turn off style sheets.
- (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 &
Implementing Guideline 3.10 Help user to use
viewports and orient within viewports.
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
- 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
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:
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.
- 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 &
- 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
- Related Resources for Success Criteria 3.10.6, 3.10.7 &
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
- 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:
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
- 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
- Related Resources for Success Criterion 3.10.12:
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
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:
- 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.
- Intent of Success Criterion 3.11.3:
- 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:
Focusable: The keyboard focus can navigate within
extensions to the user interface. (Level A)
- Intent of Success Criterion 3.11.4:
- 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:
- 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
- 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:
- 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:
- Examples of Success Criterion 3.11.7:
- Related Resources for Success Criterion 3.11.7:
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:
- Examples of Success Criterion 3.11.8:
- Related Resources for Success Criterion 3.11.8:
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:
- 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
- Intent of Success Criterion 3.11.10:
- Examples of Success Criterion 3.11.10:
- Related Resources for Success Criterion 3.11.10:
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:
- Examples of Success Criterion 3.11.11:
- Related Resources for Success Criterion 3.11.11:
Guideline 3.12 Provide alternative views.
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
- 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:
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
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
- 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
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
3.13.1 Basic Link
Information: The following information is provided for each link
- 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
- 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
- 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
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
- 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
- Related Resources for Success Criterion 4.1.1:
- Microsoft Keyboard accessibility document
- Apple keyboard
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., for access to help). (Level AA)
- Intent of Success Criterion 4.1.2:
Some users may be able to hit certain keys on the keyboard with greater
ease than others. Assistive technology software typically has extensive
keyboard commands as well. The goal of this SC is to enable the user to be
in control of what happens when a given key is pressed and use the keyboard
commands that meet his or her needs.
- Examples of Success Criterion 4.1.2:
- Laura types with one hand and finds keys on the left side of the
keyboard easier to press. She browses to a web page and notices that
the author has assigned access keys using keys from the right side of
the keyboard. She opens a dialog in the user agent and reassigns the
access keys from the web page to the left side of the keyboard home
- Elaine's screen magnification program uses alt+m to increase the size
of the magnified area of the screen. She notices that in her web
browser, alt+m is a hotkey for activating a home button that stops her
from being able to control her magnification software. She opens a
hotkey reassignment feature in the user agent, and sets alt+o to be the
new hotkey for the home button. Her screen magnification software now
- 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) 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
- 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
- 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:
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
- 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.
- 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
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
- 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
- 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:
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
- 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:
Guideline 4.4 Help users avoid flashing that could cause seizures. [Return to
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
- 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:
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:
4.5 Configure and store preference settings.
4.5.1 Change Preference
Settings The user can change settings that impact accessibility.
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)
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
- 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
- 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.
- 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
- @@ Editors' Note: Searching embedded SVG?@@
- Related Resources for Success Criterion 4.6.1:
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:
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
- 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:
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
- 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
- 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.
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:
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
- 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@@
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
- 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
- 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.
- 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
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.
Toggle: The user can turn on/off the execution of executable content
that would not normally be contained within a particular area (e.g.,
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
- 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
- The user agent provides a function that resets the playback rate to
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:
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:
4.9.7Semantic 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:
4.9.8Track 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:
4.9.9Sizing 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:
4.9.10Scale and position alternative media tracks: User can
scale and position alternative media tracks independent of base video. (Level
- 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
- 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:
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
Guideline 5.1 Help users avoid unnecessary messages. [Return to
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
- 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:
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
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.
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:
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
- 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:
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
- 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
- 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
- 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:
Language: If characteristics of the user agent involve producing an
end user experience such as speech, the user agent reacts appropriately to
- 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
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:
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.
- Level A: For Level A conformance (the minimum level of conformance), the
user agent satisfies all the Level A Success Criteria.
- Level AA: For Level AA conformance, the user agent satisfies all the
Level A and Level AA Success Criteria.
- Level AAA: For Level AAA conformance, the user agent satisfies all the
Level A, Level AA and Level AAA Success Criteria.
Note 1: Although conformance can only be achieved at the stated levels,
developers are encouraged to report (in their claim) any progress toward
meeting success criteria from all levels beyond the achieved level of
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):
on Conformance Claims
- At least one version of the conformance claim must be published on the
web as a document meeting level "A" of WCAG 2.0. A suggested metadata
description for this document is "UAAG 2.0 Conformance Claim".
- Whenever the claimed conformance level is published (e.g., product
information website), the URI for the on-line published version of the
conformance claim must be included.
- The existence of a conformance claim does not imply that the W3C has
reviewed the claim or assured its validity.
- Claimants may be anyone (e.g., user agent developers, journalists, other
- Claimants are solely responsible for the accuracy of their claims
(including claims that include products for which they are not responsible)
and keeping claims up to date.
- Claimants are encouraged to claim conformance to the most recent version
of the User Agent Accessibility Guidelines Recommendation.
Required Components of an UAAG 2.0
- Claimant name and affiliation.
- Date of the claim.
- Conformance level satisfied.
- User agent information: The name of the user agent and sufficient
additional information to specify the version (e.g., vendor name, version
number (or version range), required patches or updates, human language of
the user interface or documentation).
Note: If the user agent is a collection of software components (e.g., a
browser and extentions or plugins), then the name and version information
must be provided separately for each component, although the conformance
claim will treat them as a whole. As stated above, the Claimant has sole
responsibility for the conformance claim, not the developer of any of the
- Included Technologies: A list of the web content technologies (including
version numbers) rendered by the user agent that the Claimant is including
in the conformance claim. By including a web content technology, the
Claimant is claiming that the user agent meets the requirements of UAAG 2.0
during the rendering of web content using that web content technology.
Note 1: Web content technologies may be a combination of constituent web
content technologies. For example, an image technology (e.g., PNG) might be
listed together with a markup technology (e.g., HTML) since web content in
the markup technology is used make web content in the image technology
accessible (e.g., a PNG graph is made accessible using an HTML table).
- Excluded Technologies: A list of any web content technologies produced by
the the user agent that the Claimant is excluding from the conformance
claim. The user agent is not required to meet the requirements of UAAG 2.0
during the production of the web content technologies on this list.
- Declarations: For each success criterion: A declaration of whether or not
the success criterion has been satisfied; or
A declaration that the success criterion is not applicable and a rationale
for why not.
- Platform(s): The platform(s) upon which the user agent was evaluated: For
user agent platform(s) (used to evaluate web-based user agent user
interfaces): provide the name and version information of the user agent(s).
For platforms that are not user agents (used to evaluate non-web-based user
agent user interfaces) provide: The name and version information of the
platform(s) (e.g., operating system, etc.) and the the name and version of
the platform accessibility architecture(s) employed.
Optional Components of an UAAG 2.0
A description of how the UAAG 2.0 success criteria were met where this may
not be obvious.
Towards Conformance" Statement
Developers of user agents that do not yet conform fully to a particular UAAG
2.0 conformance level are encouraged to publish a statement on progress towards
conformance. The progress statement is the same as a conformance claim except
an UAAG 2.0 conformance level that is being progressed towards, rather than one
already satisfied, and report progress on success criteria not yet met. Authors
of "Progress Towards Conformance" Statement are solely responsible for the
accuracy of their statements. Developers are encouraged to provide expected
timelines for meeting outstanding success criteria within the Statement.
Neither W3C, WAI, nor UAWG take any responsibility for any aspect or result
of any UAAG 2.0 conformance claim that has not been published under the
authority of the W3C, WAI, or UAWG.
This glossary is normative.
- To execute or carry out the behaviors associated with
an enabled element in the rendered
content or component of the user agent user
- alternative content
- Content that is
used in place of other content that a person may not be able to access.
Alternative content fulfills essentially the same function or purpose as
the original content. Examples include text alternatives for non-text
content, captions for audio, audio descriptions for video, sign language
for audio, media alternatives for time-based media. See WCAG for more information.
- alternative content
- The set of alternative content items for a given
position in content. The items may be mutually exclusive (e.g., regular
contrast graphic vs. high contrast graphic) or non-exclusive (e.g.,
caption track that can play at the same time as a sound track).
- Graphical content that is rendered such that it can
automatically change over time, potentially giving the user a visual
perception of movement. Examples include video, animated images,
scrolling text, programmatic animation (e.g., moving or replacing
programming interface (API), conventional input/output/device
- An application programming interface (API) defines how
communication may take place between applications.
- assistive technology
- An assistive technology:
- relies on services (such as retrieving Web
resources and parsing markup) provided by one or more other
"host" user agents. Assistive technologies communicate data and
messages with host user agents by using and monitoring APIs.
- provides services beyond those offered by the host user agents to
meet the requirements of users with disabilities. Additional services
include alternative renderings (e.g., as synthesized speech or
magnified content), alternative input methods (e.g., voice),
additional navigation or orientation mechanisms, and content
transformations (e.g., to make tables more accessible).
Examples of assistive technologies that are important in the context
of UAAG 2.0 include the following:
- screen magnifiers, which are used by people with visual
disabilities to enlarge and change colors on the screen to improve
the visual readability of rendered text and images.
- screen readers, which are used by people who are blind or have
reading disabilities to read textual information through synthesized
speech or braille displays.
- voice recognition software, which may be used by people who have
some physical disabilities.
- alternative keyboards, which are used by people with certain
physical disabilities to simulate the keyboard.
- alternative pointing devices, which are used by people with certain
physical disabilities to simulate mouse pointing and button
- Beyond this document, assistive technologies consist
of software or hardware that has been specifically designed to assist
people with disabilities in carrying out daily activities. These
technologies include wheelchairs, reading machines, devices for grasping,
text telephones, and vibrating pagers. For example, the following very
general definition of "assistive technology device" comes from the (U.S.)
Assistive Technology Act of 1998 [AT1998]:
Any item, piece of equipment, or product system, whether acquired
commercially, modified, or customized, that is used to increase,
maintain, or improve functional capabilities of individuals with
- The technology of sound reproduction. Audio can be
created synthetically (including speech synthesis), streamed from a live
source (such as a radio broadcast), or recorded from real world
- audio description - also called
described video, video description and descriptive narration
- An equivalent alternative that takes the form of narration added to the
audio to describe important visual details that
cannot be understood from the main soundtrack alone. Audio description of
video provides information about actions, characters, scene changes,
on-screen text, and other visual content. In standard audio description,
narration is added during existing pauses in dialogue. In extended audio
description, the video is paused so that there is time to add
- The people who have worked either alone or collaboratively to create
the content (includes content authors, designers, programmers,
publishers, testers, etc.).
- author styles
- Style property
values that are set by the author as part of the content.
- Images that are rendered on the base background.
- The background of the content as a whole, such that no
content may be layered behind it. In graphics applications, the base
background is often referred to as the canvas.).
- Text whose visual rendering alternates between visible and invisible at
any rate of change.
- An equivalent alternative that takes the form of text presented and
synchronized with time-based media to provide not only the
speech, but also non-speech information conveyed through sound, including
meaningful sound effects and identification of speakers. In some
countries, the term "subtitle" is used to refer to dialogue only and
"captions" is used as the term for dialogue plus sounds and speaker
identification. In other countries, "subtitle" (or its translation) is
used to refer to both. Open captions are captions that are
always rendered with a visual track; they cannot be turned off.
Closed captions are captions that may be turned on and off.
The captions requirements of UAAG 2.0 assume that the user agent can recognize the captions as such.
Note: Other terms that include the word "caption" may
have different meanings in UAAG 2.0. For instance, a "table caption" is a
title for the table, often positioned graphically above or below the
table. In UAAG 2.0, the intended meaning of "caption" will be clear from
- collated text transcript
- A collated text transcript is a text equivalent of a movie or
other animation. More specifically, it is the combination of the text transcript of the audio track and the text equivalent
of the visual track. For example, a
collated text transcript typically includes segments of spoken dialogue
interspersed with text descriptions of the key visual elements of a
presentation (actions, body language, graphics, and scene changes). See
also the definitions of text
transcript and audio description. Collated
text transcripts are essential for individuals who are deaf-blind.
- content (Web
- Information and sensory experience to be communicated
to the user by means of a user agent, including code or markup that
defines the content's structure, presentation, and interactions [adapted
from WCAG 2.0]
content (which may be alternative content) is
either a null value or an empty string (i.e., one that is zero characters
long). For instance, in HTML,
alt="" sets the value of the
alt attribute to the empty string. In some markup languages,
an element may have empty content (e.g., the
HR element in
- document character set
- The internal representation of data in the source
content by a user agent.
- document object, Document Object Model
- The Document Object Model is a platform- and
language-neutral interface that allows programs and scripts to
dynamically access and update the content, structure and style of
documents. The document can be further processed and the results of that
processing can be incorporated back into the presented page. This is an
overview of DOM-related materials here at W3C and around the web: http://www.w3.org/DOM/#what.
- document source, text source
- Text the user agent renders upon user request to view
the source of specific viewport content (i.e. selected content, frame,
- Any information that supports the use of a user agent.
This information may be found, for example, in manuals, installation
instructions, the help system, and tutorials. Documentation may be
distributed (e.g., as files installed as part of the installation, some
parts may be delivered on CD-ROM, others on the Web). See guideline 5.3 for information about
- element, element type
- UAAG 2.0 uses the terms "element" and "element type"
primarily in the sense employed by the XML 1.0 specification ([XML], section
3): an element type is a syntactic construct of a document type
definition (DTD) for its application. This sense is also relevant to
structures defined by XML schemas. The document also uses the term
"element" more generally to mean a type of content (such as video or
sound) or a logical construct (such as a header or list).
- enabled element, disabled
- An element with associated
behaviors that can be activated through the user interface or through an
set of elements that a user agent enables is generally derived from, but
is not limited to, the set of elements defined by
implemented markup languages. A disabled element is a potentially enabled
element, that is not currently available for activation (e.g., a "grayed
out" menu item).
- equivalent alternative
- Content that is an acceptable substitute for other
content that a person may not be able to access. An equivalent
alternative fulfills essentially the same function or purpose as the
original content upon presentation:
- text alternative [WCAG 2.0]: text that is available via the operating environment
that is used in place of non-text content (e.g., text equivalents for
images, text transcripts for audio tracks, or collated text
transcripts for a movie).
- full text alternative for synchronized media including any
interaction [WCAG 2.0]:
document including correctly sequenced text descriptions of all
visual settings, actions, speakers, and non-speech sounds, and
transcript of all dialogue combined with a means of achieving any
outcomes that are achieved using interaction (if any) during the
- synchronized alternatives: present essential audio information
visually (i.e., captions) and essential video information in an
auditory manner (i.e., audio descriptions). [from ATAG 2.0]
- events and
scripting, event handler, event type
- User agents often perform a task when an event having
a particular "event type" occurs, including user interface events,
changes to content, loading of content, and requests from the operating environment. Some
markup languages allow authors to specify that a script, called an event
handler, be executed when an event of a given type occurs. An
event handler is explicitly associated with an
element through scripting, markup or the DOM.
- explicit user request
- Any user interaction by the user through the user agent user
interface, the focus, or the selection. User
requests are made, for example, through user
agent user interface controls and keyboard bindings.
Some examples of explicit user requests include when the user selects
"New viewport," responds "yes" to a prompt in the user agent's user
interface, configures the user agent to behave in a certain way, or
changes the selection or focus with the keyboard or pointing device.
Note: Users can make errors when interacting with the
user agent. For example, a user may inadvertently respond "yes" to a
prompt instead of "no." In UAAG 2.0, this type of error is still
considered an explicit user request.
- focus (includes: active input focus, active
selection, cursor, focus cursor, focusable element, highlight, inactive input
focus, inactive selection, input focus, keyboard focus, pointer, pointing
device focus, selection, split focus, text cursor)
Hierarchical Summary of some focus terms
- Input Focus (active/inactive)
- Keyboard Focus (active/inactive)
- Cursor (active/inactive)
- Focus cursor (active/inactive)
- Text cursor (active/inactive)
- Pointing device focus (active/inactive)
- active input focus
- The input focus location in the active
viewport. The active focus is in the active
viewport, while the inactive input focus is the inactive viewport. The active input focus is usually visibly
indicated. In UAAG 2.0 "active input focus" generally refers to the
active keyboard input focus. @@ Editors' Note:
this term is not used in the document other than the
- active selection
- The selection that will currently be affected by a user command, as
opposed to selections in other viewports, called inactive selections,
which would not currently be affected by a user command. @@ Editors' Note: this term is not used in the
document other than the glossary.@@
- Visual indicator showing where keyboard input will occur. There are two
types of cursors: focus cursor (e.g. the
dotted line around a button) and text
cursor (e.g. the flashing vertical bar in a text field, also called a
'caret'). Cursors are active when in the active viewport, and inactive
when in an inactive viewport.
- focus cursor
- Indicator that highlights a user interface
element to show that it has keyboard
focus, e.g. a dotted line around a button, or brightened title bar on
a window. There are two types of cursors: focus cursor (e.g. the dotted
line around a button) and text cursor (e.g. the flashing
vertical bar in a text field).
- focusable element
- Any element capable of having input
focus, e.g. link, text box, or menu item. In order to be accessible
and fully usable, every focusable element should take keyboard focus, and ideally would also
take pointer focus.
- highlight, highlighted,
- Emphasis indicated through the user interface. For example, user agents
highlight content that is selected,focused, or matched by a search
operation. Graphical highlight mechanisms include dotted boxes, changed
colors or fonts, underlining, magnification, and reverse video.
Synthesized speech highlight mechanisms include alterations of voice
pitch and volume ("speech prosody"). User interface items may also be
highlighted, for example a specific set of foreground and background
colors for the title bar of the active window. Note that content that is
highlighted may or may not be a selection.
- inactive input focus
- An input focus location in an inactive viewport such as a background
window or pane. The inactive input focus location will become the active
input focus location when input focus returns to that viewport. An
inactive input focus may or may not be visibly indicated.
- inactive selection
- A selection that does not have the input
focus and thus does not take input events.
- input focus
- The place where input will occur if a viewport is active. Examples
include keyboard focus and pointing device focus. Input focus can also be
active (in the active viewport) or inactive (in an inactive viewport).
- keyboard focus
- The screen location where keyboard input will occur if a viewport is
active. Keyboard focus can be active (in the active viewport) or inactive
(in an inactive viewport).
- Visual indicator showing where pointing device input will occur. The
indicator can be moved with a pointing device or emulator such as a
mouse, pen tablet, keyboard-based mouse emulator, speech-based mouse
commands, or 3-D wand. A pointing device click typically moves the input focus to the pointer location. The
indicator may change to reflect different states. NOTE:
When touch screens are used, the "pointing device" is a combination of
the touch screen and the user's finger or stylus. On most systems there
is no pointer (on-screen visual indication) associated with this type of
- pointing device focus
- The screen location where pointer input will occur if a viewport is
active. There can be multiple pointing device foci, for example when
using a screen sharing utility there is typically one for the user's
physical mouse and one for the remote mouse. @@ Editors' Note: this term is not used in the
document other than the glossary.@@
- A user agent mechanism for identifying a (possibly empty) range of
content that will be the implicit source or target for subsequent
operations. The selection may be used for a variety of purposes,
including for cut and paste operations, to designate a specific element
in a document for the purposes of a query, and as an indication of point
of regard, e.g. the matched results of a search may be automatically
selected. The selection should be highlighted in a distinctive manner. On the
screen, the selection may be highlighted in a variety of ways, including
through colors, fonts, graphics, and magnification. When rendered using
synthesized speech, the selection may be highlighted through changes in
pitch, speed, or prosody.
- split focus
- A state when the user could be confused because the input focus is
separated from something it is usually linked to, such as being at a
different place than the selection or similar highlighting, or has been
scrolled outside of the visible portion of the viewport. @@ Editors' Note: this term is not used in the
document other than the glossary.@@
- text cursor
- Indicator showing where keyboard input will occur in text (e.g. the
flashing vertical bar in a text field, also called a caret).
- content focus, user interface focus, current focus
@@ Editor's Note: Need to find the hrefs to
these definitions and fix them. @@
- globally, global
- @@ Editors' Note: Needs to
- Information (including text, colors, graphics, images,
and animations) rendered for visual consumption.
- To emphasize through the user interface. For example,
user agents highlight which content is selected or focused. Graphical
highlight mechanisms include dotted boxes, underlining, a user-adjustable
combination of foreground and background colors, and reverse video.
Synthesized speech highlight mechanisms include alterations of voice
pitch and volume ("speech prosody").
- Pictorial content that is static (i.e.not moving or
changing). See also the definition of animation.
- important elements
- This specification intentionally does not identify
which "important elements" must be navigable as this will vary by
specification. What constitutes "efficient navigation" may depend on a
number of factors as well, including the "shape" of content (e.g.,
sequential navigation of long lists is not efficient) and desired
granularity (e.g., among tables, then among the cells of a given table).
Refer to the Implementing document [Implementing UAAG 2.0] for
information about identifying and navigating important elements. @@ Editors' Note: Update links
- input configuration
- The set of "bindings" between user agent
functionalities and user interface input mechanisms
(e.g., menus, buttons, keyboard keys, and voice commands). The default
input configuration is the set of bindings the user finds after
installation of the software. Input configurations may be affected by
author-specified bindings (e.g., through the
attribute of HTML 4 [HTML4]).
- keyboard command
- Direct Commands* (also called keyboard shortcuts or accelerator
keys) are those tied to particular UI controls or application
functions, allowing the user to navigate-to or activate them without
traversing any intervening controls (e.g., "ctrl"+"S" to save a
document). It is sometimes useful to distinguish direct commands that are
associated with controls that are rendered in the current context (e.g.,
"alt"+"D" to move focus to the address bar) from those that may be able
to activate program functionality that is not associated with any
currently rendered controls (e.g., "F1" to open the Help system). Direct
commands help users accelerate their selections.
- natural language
- Natural language is spoken, written, or signed human
language such as French, Japanese, and American Sign Language. On the
Web, the natural language of content may be specified by markup or
HTTP headers. Some examples include the
attribute in HTML 4 ([HTML4] section 8.1), the
attribute in XML 1.0 ([XML], section 2.12), the
attribute for links in HTML 4 ([HTML4],
section 12.1.5), the HTTP Content-Language header ([RFC2616], section 14.12)
and the Accept-Language request header ([RFC2616], section 14.4).
See also the definition of script.
- normative, informative [WCAG 2.0, ATAG
- What is identified as "normative" is required for conformance (noting that one may conform in a
variety of well-defined ways to UAAG 2.0). What is identified as
"informative" (sometimes, "non-normative") is never required for
- To make the user aware of events or status changes.
Notifications can occur within the user agent user interface (e.g.,
status bar) or within the content display. Notifications may be passive
and not require user acknowledgment, or they may be presented in the form
of a prompt requesting a user response (e.g., a confirmation dialog).
- operating environment
- The term "operating environment" refers to the
environment that governs the user agent's operation, whether it is an
operating system or a programming language environment such as Java.
- In UAAG 2.0, the term "override" means that one
configuration or behavior preference prevails over another. Generally,
the requirements of UAAG 2.0 involve user preferences prevailing over
author preferences and user agent default settings and behaviors.
Preferences may be multi-valued in general (e.g., the user prefers blue
over red or yellow), and include the special case of two values (e.g.,
turn on or off blinking text content).
- A placeholder is content generated by the user agent
to replace author-supplied content. A placeholder may be generated as the
result of a user preference (e.g., to not render images) or as repair content (e.g., when an
image cannot be found). Placeholders can be any type of content,
including text, images, and audio cues. Placeholders should identify the
technology of the object of which it is holding the place. Placeholders
will appear in the alternative content stack.
- platform accessibility
- A programmatic interface that is specifically engineered to enhance
communication between mainstream software applications and assistive
technologies (e.g., MSAA, UI Automation, and IAccessible2 for Windows
applications, AXAPI for MacOSX applications, Gnome Accessibility Toolkit
API for Gnome applications, Java Access for Java applications, etc.). On
some platforms it may be conventional to enhance communication further
via implementing a DOM.
- plug-in [ATAG
- A plug-in is a program that runs as part of the user
agent and that is not part of content. Users
generally choose to include or exclude plug-ins from their user
- point of regard
- The point of regard is a position in rendered content that the user
is presumed to be viewing. The dimensions of the point of regard may
vary. For example, it may be a point (e.g., a moment during an audio
rendering or a cursor position in a graphical rendering), or a range of
text (e.g., focused text), or a two-dimensional area (e.g., content
rendered through a two-dimensional graphical viewport). The point of
regard is almost always within the viewport, but it may exceed the
spatial or temporal dimensions of the
viewport (see the definition of rendered content for more
information about viewport dimensions). The point of regard may also
refer to a particular moment in time for content that changes over time
(e.g., an audio-only presentation). User agents may determine the point
of regard in a number of ways, including based on viewport position in
content, content focus, and selection. The stability of the point
of regard is addressed by @@.
- A profile is a named and persistent representation of
user preferences that may be used to configure a user agent. Preferences
include input configurations, style preferences, and natural language
preferences. In operating environments with
distinct user accounts, profiles enable users to reconfigure software
quickly when they log on. Users may share their profiles with one
another. Platform-independent profiles are useful for those who use the
same user agent on different platforms.
- prompt [ATAG
- Any user agent initiated request for a decision or piece of information
- properties, values, and
- A user agent renders a document by applying formatting
algorithms and style information to the document's elements. Formatting
depends on a number of factors, including where the document is rendered:
on screen, on paper, through loudspeakers, on a braille display, or on a
mobile device. Style information (e.g., fonts, colors, and synthesized
speech prosody) may come from the elements themselves (e.g., certain font
and phrase elements in HTML), from style sheets, or from user agent
settings. For the purposes of these guidelines, each formatting or style
option is governed by a property and each property may take one value
from a set of legal values. Generally in this document, the term "property"
has the meaning defined in CSS 2 ([CSS2], section 3). A reference
to "styles" in UAAG 2.0 means a set of style-related properties. The
value given to a property by a user agent at installation is called the
- Authors encode information in many ways, including in
markup languages, style sheet languages, scripting languages, and
protocols. When the information is encoded in a manner that allows the
user agent to process it with certainty, the user agent can "recognize"
the information. For instance, HTML allows authors to specify a heading
H1 element, so a user agent that implements HTML
can recognize that content as a heading. If the author creates a heading
using a visual effect alone (e.g., just by increasing the font size),
then the author has encoded the heading in a manner that does not allow
the user agent to recognize it as a heading.
Some requirements of UAAG 2.0 depend on content roles, content
relationships, timing relationships, and other information supplied by
the author. These requirements only apply when the author has encoded
that information in a manner that the user agent can recognize. See the
section on conformance for more information
In practice, user agents will rely heavily on information that the
author has encoded in a markup language or style sheet language. On the
other hand, behaviors, style, meaning encoded in a script, and markup in an unfamiliar XML
namespace may not be recognized by the user agent as easily or at all.
The Techniques document [UAAG10-TECHS] lists
some markup known to affect accessibility that user agents can
- rendered content, rendered
- Rendered content is the part of content that the user agent makes
available to the user's senses of sight and hearing (and only those
senses for the purposes of UAAG 2.0). Any content that causes an effect
that may be perceived through these senses constitutes rendered content.
This includes text characters, images, style sheets, scripts, and
anything else in content that, once processed, may be perceived through
sight and hearing.
- The term "rendered text" refers to text
content that is rendered in a way that communicates information about the
characters themselves, whether visually or as synthesized speech.
- In the context of UAAG 2.0, invisible
content is content that is not rendered but that may influence
the graphical rendering (e.g., layout) of other content. Similarly, silent
content is content that is not rendered but that may influence
the audio rendering of other content. Neither invisible nor silent
content is considered rendered content.
- repair content, repair text
- In UAAG 2.0, the term "repair content" refers to
content generated by the user agent in order to correct an error
condition. "Repair text" refers to the text portion of repair
content. Some error conditions that may lead to the generation of repair
- Erroneous or incomplete content (e.g., ill-formed markup, invalid
markup, or missing alternative content that
is required by format specification);
- Missing resources for handling or rendering content (e.g., the user
agent lacks a font family to display some characters, or the user
agent does not implement a particular scripting language).
UAAG 2.0 does not require user agents to include repair content in the
document object. Repair content
inserted in the document object should conform to the Web Content
Accessibility Guidelines 1.0 [WCAG10]. For more
information about repair techniques for Web content and software, refer
to "Techniques for Authoring Tool Accessibility Guidelines 1.0" [ATAG10-TECHS].
- In UAAG 2.0, the term "script" almost always refers to
a scripting (programming) language used to create dynamic Web content.
However, in guidelines referring to the written (natural) language of
content, the term "script" is used as in Unicode [UNICODE] to mean "A
collection of symbols used to represent textual information in one or
more writing systems."
- Information encoded in (programming) scripts may be
difficult for a user agent to recognize. For
instance, a user agent is not expected to recognize that, when executed,
a script will calculate a factorial. The user agent will be able to
recognize some information in a script by virtue of implementing the
scripting language or a known program library (e.g., the user agent is
expected to recognize when a script will open a viewport or retrieve a
resource from the Web).
- selection, current
- In UAAG 2.0, the term "selection" refers to a user
agent mechanism for identifying a (possibly empty) range of content. Generally, user agents limit the
type of content that may be selected to text content (e.g., one or more
fragments of text). In some user agents, the value of the selection is constrained by the
structure of the document tree.
On the screen, the selection may be highlighted in a
variety of ways, including through colors, fonts, graphics, and
magnification. The selection may also be highlighted when rendered as
synthesized speech, for example through changes in speech prosody. The
dimensions of the rendered selection may exceed those of the viewport.
The selection may be used for a variety of purposes, including for cut
and paste operations, to designate a specific element in a document for
the purposes of a query, and as an indication of point of
The selection has state, i.e., it may be "set," programmatically or
through the user interface.
In UAAG 2.0, each viewport is expected to have at most one selection.
When several viewports coexist, at most one
viewport's selection responds to input events; this is called the current
Note: Some user agents may also implement a selection
for designating a range of information in the user
agent user interface. The current document only includes requirements
for a content selection mechanism.
- serial access, sequential navigation
- In UAAG 2.0, the expression "serial access" refers to
one-dimensional access to rendered
content. Some examples of serial access include listening to an audio
stream or watching a video (both of which involve one temporal
dimension), or reading a series of lines of braille one line at a time
(one spatial dimension). Many users with blindness have serial access to
content rendered as audio, synthesized speech, or lines of braille.
The expression "sequential navigation" refers to navigation through an
ordered set of items (e.g., the enabled
elements in a document, a sequence of lines or pages, or a sequence
of menu options). Sequential navigation implies that the user cannot skip
directly from one member of the set to another, in contrast to direct or
structured navigation. Users with blindness or some users with a physical
disability may navigate content sequentially (e.g., by navigating through
links, one by one, in a graphical viewport with or without the aid of an
assistive technology). Sequential navigation is important to users who
cannot scan rendered content visually for context and also benefits users
unfamiliar with content. The increments of sequential navigation may be
determined by a number of factors, including element type (e.g., links
only), content structure (e.g., navigation from heading to heading), and
the current navigation context (e.g., having navigated to a table, allow
navigation among the table cells).
Users with serial access to content or who navigate sequentially may
require more time to access content than users who use direct or
- support, implement, conform
- In UAAG 2.0, the terms "support," "implement," and
"conform" all refer to what a developer has designed a user agent to do,
but they represent different degrees of specificity. A user agent
"supports" general classes of objects, such as "images" or "Japanese." A
user agent "implements" a specification (e.g., the PNG and SVG image
format specifications or a particular scripting language), or an API
(e.g., the DOM API) when it has been programmed to follow all or part of
a specification. A user agent "conforms to" a specification when it
implements the specification and satisfies its conformance
- In UAAG 2.0, "to synchronize" refers to the act of
time-coordinating two or more presentation components (e.g., a visual track with captions, or
several tracks in a multimedia presentation). For Web content developers,
the requirement to synchronize means to provide the data that will permit
sensible time-coordinated rendering by a user agent. For example, Web
content developers can ensure that the segments of caption text are
neither too long nor too short, and that they map to segments of the
visual track that are appropriate in length. For user agent developers,
the requirement to synchronize means to present the content in a sensible
time-coordinated fashion under a wide range of circumstances including
technology constraints (e.g., small text-only displays), user limitations
(slow reading speeds, large font sizes, high need for review or repeat
functions), and content that is sub-optimal in terms of
- technology (Web content) - or
shortened to technology [WCAG 2.0, ATAG
- A mechanism for encoding instructions to be rendered, played or
executed by user agents. Web Content
technologies may include markup languages, data formats, or programming
languages that authors may use alone or in
combination to create end-user experiences that range from static Web
pages to multimedia presentations to dynamic Web applications. Some
common examples of Web content technologies include HTML, CSS, SVG, PNG,
- In UAAG 2.0, the term "text" used by itself refers to
a sequence of characters from a markup language's document character set.
Refer to the "Character Model for the World Wide Web" [CHARMOD] for more
information about text and characters. Note: This
document makes use of other terms that include the word "text" that have
highly specialized meanings: collated text
transcript, non-text content, text content, non-text element, text element, text equivalent, and text transcript.
- text content, non-text
element, non-text element, text equivalent, non-text
- As used in UAAG 2.0 a "text element" adds text
characters to either content or the user
interface. Both in the Web Content Accessibility Guidelines 1.0
[WCAG10] and in this
document, text elements are presumed to produce text that can be
understood when rendered visually, as synthesized speech, or as Braille.
Such text elements benefit at least these three groups of users:
- visually-displayed text benefits users who are deaf and adept in
reading visually-displayed text;
- synthesized speech benefits users who are blind and adept in use of
- braille benefits users who are blind, and possibly deaf-blind, and
adept at reading braille.
A text element may consist of both text and non-text data. For
instance, a text element may contain markup for style (e.g., font size or
color), structure (e.g., heading levels), and other semantics. The
essential function of the text element should be retained even if style
information happens to be lost in rendering.
A user agent may have to process a text element in order to have
access to the text characters. For instance, a text element may consist
of markup, it may be encrypted or compressed, or it may include embedded
text in a binary format (e.g., JPEG).
"Text content" is content that is composed of one or more text
elements. A "text equivalent" (whether in content or the user interface)
is an equivalent composed of
one or more text elements. Authors generally provide text equivalents for
content by using the alternative content
mechanisms of a specification.
A "non-text element" is an element (in content or the user interface)
that does not have the qualities of a text element. "Non-text content" is
composed of one or more non-text elements. A "non-text equivalent"
(whether in content or the user interface) is an equivalent composed of
one or more non-text elements.
- text decoration
- In UAAG 2.0, a "text decoration" is any stylistic
effect that the user agent may apply to visually rendered
text that does not affect the layout of the document (i.e., does not
require reformatting when applied or removed). Text decoration mechanisms
include underline, overline, and strike-through.
- Any media object given an Internet media type of
"text" (e.g., "text/plain", "text/html", or "text/*") as defined in RFC
2046 [RFC2046], section 4.1, or
any media object identified by Internet media type to be an XML document
(as defined in [XML], section 2) or SGML
application. Refer, for example, to Internet media types defined in "XML
Media Types" [RFC3023].
- text transcript
- A text transcript is a text equivalent of audio
information (e.g., an audio-only presentation or the audio track of a movie or other
animation). It provides text for both spoken words and non-spoken sounds
such as sound effects. Text transcripts make audio information accessible
to people who have hearing disabilities and to people who cannot play the
audio. Text transcripts are usually created by hand but may be generated
on the fly (e.g., by voice-to-text converters). See also the definitions
of captions and collated text
- track (audio track or visual track)
- Content rendered as sound through an
audio viewport. The audio track may be all or
part of the audio portion presentation (e.g., each instrument may have a
track, or each stereo channel may have a track). Also see definition of
- user agent
- A user agent is any software that retrieves, renders
and facilitates end user interaction with Web content.
- user agent default styles
- User agent default styles are style property
values applied in the absence of any author or user styles. Some
markup languages specify a default rendering for content in that markup
language; others do not. For example, XML 1.0 [XML] does not
specify default styles for XML documents. HTML 4
[HTML4] does not specify
default styles for HTML documents, but the CSS 2 [CSS2]
specification suggests a sample
default style sheet for HTML 4 based on current practice.
- user interface, user interface
- For the purposes of UAAG 2.0, user interface includes
The document distinguishes them only where required for clarity. For more
information, see the section on requirements for content, for user agent
features, or both @@.
- the user agent user
interface, i.e., the controls (e.g., menus, buttons,
prompts, and other components for input and output) and mechanisms
(e.g., selection and focus) provided by the user agent ("out of the
box") that are not created by content.
- the "content user interface," i.e., the enabled elements that are
part of content, such as form controls, links, and applets.
The term "user interface control" refers to a component of the user
agent user interface or the content user interface, distinguished where
- User styles are style property
values that come from user interface settings, user style sheets, or
other user interactions.
- view, viewport
- The user agent renders
content through one or more viewports. Viewports include windows,
frames, pieces of paper, loudspeakers, and virtual magnifying glasses. A
viewport may contain another viewport (e.g., nested frames). User agent user interface
controls such as prompts, menus, and alerts are not viewports.
Graphical and tactile viewports have two spatial dimensions. A viewport may also
have temporal dimensions, for instance when audio, speech, animations,
and movies are rendered. When the dimensions (spatial or temporal) of
rendered content exceed the dimensions of the viewport, the user agent
provides mechanisms such as scroll bars and advance and rewind controls
so that the user can access the rendered content "outside" the viewport.
Examples include: when the user can only view a portion of a large
document through a small graphical viewport, or when audio content has
already been played.
When several viewports coexist, only one has the current focus at a given moment.
This viewport is highlighted to make it stand out.
User agents may render the same content in a variety of ways; each
rendering is called a view. For instance, a user agent may allow
users to view an entire document or just a list of the document's
headers. These are two different views of the document.
"top-level" viewports are viewports
that are not contained within other user agent viewports.
- visual-only presentation
- A visual-only presentation is content consisting
exclusively of one or more visual
tracks presented concurrently or in series. A silent movie is an
example of a visual-only presentation.
- visual track
- A visual object is content rendered through a
graphical viewport. Visual objects include
graphics, text, and visual portions of movies and other animations. A
visual track is a visual object that is intended as a whole or partial
presentation. A visual track does not necessarily correspond to a single
physical object or software object.
- voice browser
- From "Introduction and Overview of W3C Speech
Interface Framework" [VOICEBROWSER]: "A
voice browser is a device (hardware and software) that interprets voice
markup languages to generate voice output, interpret voice input, and
possibly accept and produce other modalities of input and output."
- web resource
- Anything that can be identified by a Uniform Resource Identifier
Appendix B: How to refer to
UAAG 2.0 from other documents
@@ Editors' Note: This section is still under
Appendix C: References
This section is informative.
For the latest version of any W3C specification please
consult the list of W3C Technical Reports at
http://www.w3.org/TR/. Some documents listed below may have been superseded
since the publication of UAAG 2.0.
Note: In UAAG 2.0, bracketed labels such as "[WCAG20]" link
to the corresponding entries in this section. These labels are also identified
as references through markup.
Style Sheets (CSS1) Level 1 Specification," B. Bos, H. Wium
Lie, eds., 17 December 1996, revised 11 January 1999. This W3C
Recommendation is http://www.w3.org/TR/1999/REC-CSS1-19990111.
Style Sheets, level 2 (CSS2) Specification," B. Bos, H. Wium
Lie, C. Lilley, and I. Jacobs, eds., 12 May 1998. This W3C Recommendation
Object Model (DOM) Level 2 Core Specification," A. Le Hors, P.
Le Hégaret, L. Wood, G. Nicol, J. Robie, M. Champion, S. Byrne, eds., 13
November 2000. This W3C Recommendation is
Object Model (DOM) Level 2 Style Specification," V. Apparao,
P. Le Hégaret, C. Wilson, eds., 13 November 2000. This W3C
Information Set," J. Cowan and R. Tobin, eds., 24 October
2001. This W3C Recommendation is
Internet Mail Extensions (MIME) Part Two: Media Types," N.
Freed, N. Borenstein, November 1996.
Content Accessibility Guidelines 1.0," W. Chisholm, G.
Vanderheiden, and I. Jacobs, eds., 5 May 1999. This W3C Recommendation is
Markup Language (XML) 1.0 (Second Edition)," T. Bray, J.
Paoli, C.M. Sperberg-McQueen, eds., 6 October 2000. This W3C
Recommendation is http://www.w3.org/TR/2000/REC-xml-20001006.
- The Assistive Technology
Act of 1998.
- "Authoring Tool
Accessibility Guidelines 1.0," J. Treviranus, C.
McCathieNevile, I. Jacobs, and J. Richards, eds., 3 February 2000. This
W3C Recommendation is http://www.w3.org/TR/2000/REC-ATAG10-20000203/.
for Authoring Tool Accessibility Guidelines 1.0," J.
Treviranus, C. McCathieNevile, J. Richards, eds., 29 Oct 2002. This W3C
Note is http://www.w3.org/TR/2002/NOTE-ATAG10-TECHS-20021029/.
- "Character Model
for the World Wide Web," M. Dürst and F. Yergeau, eds., 30
April 2002. This W3C Working Draft is
http://www.w3.org/TR/2002/WD-charmod-20020430/. The latest version is available at
Object Model (DOM) Level 2 HTML Specification," J. Stenback,
P. Le Hégaret, A. Le Hors, eds., 8 November 2002. This W3C Proposed
http://www.w3.org/TR/2002/PR-DOM-Level-2-HTML-20021108/. The latest version is
available at http://www.w3.org/TR/DOM-Level-2-HTML/.
4.01 Recommendation," D. Raggett, A. Le Hors, and I. Jacobs,
eds., 24 December 1999. This W3C Recommendation is
- "Hypertext Transfer
Protocol — HTTP/1.1," J. Gettys, J. Mogul, H. Frystyk, L.
Masinter, P. Leach, T. Berners-Lee, June 1999.
- "XML Media
Types," M. Murata, S. St. Laurent, D. Kohn, January 2001.
Multimedia Integration Language (SMIL) 1.0 Specification," P.
Hoschka, ed., 15 June 1998. This W3C Recommendation is
Multimedia Integration Language (SMIL 2.0) Specification," J.
Ayars, et al., eds., 7 August 2001. This W3C Recommendation is
Vector Graphics (SVG) 1.0 Specification," J. Ferraiolo, ed., 4
September 2001. This W3C Recommendation is
- "User Agent
Accessibility Guidelines 1.0," I. Jacobs, J. Gunderson, E. Hansen,
eds.17 December 2002. This W3C Recommendation is available at
- An appendix to UAAG 2.0 lists all of the checkpoints, sorted by
priority. The checklist is available in either tabular
form or list
- Information about UAAG 1.0 conformance
icons and their usage is available at
- An appendix to UAAG 2.0 provides a summary of the goals and structure of User Agent
Accessibility Guidelines 1.0.
- "Techniques for User
Agent Accessibility Guidelines 1.0," I. Jacobs, J. Gunderson,
E. Hansen, eds. The latest draft of the techniques document is available
- "The Unicode
Standard, Version 3.2." This technical report of the Unicode Consortium is available at
http://www.unicode.org/reports/tr28/. This is a revision of "The Unicode
Standard, Version 3.0," The Unicode Consortium, Addison-Wesley Developers
Press, 2000. ISBN 0-201-61633-5. Refer also to http://www.unicode.org/standard/versions/.
For information about character encodings, refer to Unicode Technical Report #17
"Character Encoding Model".
and Overview of W3C Speech Interface Framework," J. Larson, 4
December 2000. This W3C Working Draft is
http://www.w3.org/TR/2000/WD-voice-intro-20001204/. The latest version is available
at http://www.w3.org/TR/voice-intro/. UAAG 2.0 includes references to
additional W3C specifications about voice browser technology.
Wide Web Consortium Process Document," I. Jacobs ed. The 19
July 2001 version of the Process Document is
http://www.w3.org/Consortium/Process-20010719/. The latest version is
available at http://www.w3.org/Consortium/Process/.
- "Techniques for Web
Content Accessibility Guidelines 1.0," W. Chisholm, G.
Vanderheiden, and I. Jacobs, eds., 6 November 2000. This W3C Note is
http://www.w3.org/TR/2000/NOTE-WCAG10-TECHS-20001106/. The latest version is available
at http://www.w3.org/TR/WCAG10-TECHS/. Additional format-specific
techniques documents are available from this Note.
Characterization Terminology and Definitions Sheet," B.
Lavoie, H. F. Nielsen, eds., 24 May 1999. This is a W3C Working Draft
that defines some terms to establish a common understanding about key Web
concepts. This W3C Working Draft is
Accessibility Guidelines 1.0," D. Dardailler, S. Palmer, C.
McCathieNevile, eds., 3 October 2001. This W3C Working Draft is
http://www.w3.org/TR/2002/WD-xag-20021003. The latest version is available at
- "XHTML[tm] 1.0: The
Extensible HyperText Markup Language," S. Pemberton, et al.,
26 January 2000. This W3C Recommendation is
Syntax and Processing," D. Eastlake, J. Reagle, D. Solo, eds.,
12 February 2002. This W3C Recommendation is
Encryption Syntax and Processing," D. Eastlake, J. Reagle,
eds., 10 December 2002. This W3C Recommendation is
active in the UAWG prior publication:
- Jim Allan (Co-Chair, Texas School for the Blind and Visually
- Alan Cantor (Invited Expert)
- Bim Egan (Royal National Institute of Blind People)
- Kelly Ford (Co-Chair, Microsoft)
- Mark Hakkinen (Invited Expert)
- Simon Harper (University of Manchester)
- Patrick Lauke (Opera Software)
- Greg Lowney (Invited Expert)
- Kimberly Patch (Invited Expert)
- Jan Richards (Adaptive Technology Resource Centre, University of
- Jeanne Spellman (W3C Staff Contact)
previously active UAWG participants and other contributors to UAAG 2.0:
- Judy Brewer (W3C)
- Sean Hayes, Microsoft
- Dean Hudson, Apple
- Cathy Laws (IBM)
- Peter Parente (IBM)
- David Poehlman (Invited Expert)
- Simon Pieters, Opera Software
- Henny Swan (Opera)
- Gregory Rosmaita (Invited Expert)
- David Tseng (Apple)
UAAG 2.0 would not have been possible without the work of those who
contributed to UAAG 1.0.
This publication has been funded in part with Federal funds from the U.S.
Department of Education, National Institute on Disability and Rehabilitation
Research (NIDRR) under contract number ED-OSE-10-C-0067. The content of this
publication does not necessarily reflect the views or policies of the U.S.
Department of Education, nor does mention of trade names, commercial products,
or organizations imply endorsement by the U.S. Government.
Appendix E: Checklist
@@ Editors' Note: This section is still under
Comparison of UAAG 1.0 guidelines to UAAG 2.0
@@ Editors' Note: This section is still under
Appendix G: Alternative Content
These are the elements and attributes that present 'alternative content'
relevant to Guideline 3.
@@ Editors' Note: This needs update and permanent links
as HTML5 goes to rec. Get listings of alternative content for other
technologies. Think about better format for presenting it.