UAAG 2.0 provides guidelines 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 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 disabilities.
The "User Agent Accessibility Guidelines 2.0" (UAAG 2.0) is part of
a series of accessibility guidelines published by the W3C Web Accessibility
Initiative (WAI).
May be
Superseded
This section describes the status of this document at the time of its
publication. Other documents may supersede this document. A list of current
W3C publications and
the latest revision of this technical report can be found in the W3C technical reports index
at http://www.w3.org/TR/.
Editor's Draft of UAAG
2.0
This document is the internal working draft used by the UAWG and is updated continuously and
without notice. This document has no formal standing within W3C. Please consult
the group's home page and the W3C technical reports index for information
about the latest publications by this group.
Web Accessibility Initiative
This document has been produced as part of the W3C Web Accessibility Initiative (WAI). The goals
of the User Agent Working Group (UAWG) are discussed in the Working Group charter. The
UAWG is part of the WAI Technical Activity.
No
Endorsement
Publication as a Working Draft does not imply endorsement by the W3C Membership. This is a draft
document and may be updated, replaced or obsoleted by other documents at any
time. It is inappropriate to cite this document as other than work in progress.
Patents
This document was produced by a group operating under the 5 February 2004 W3C
Patent Policy. 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.
This section is informative.
A user agent is any software that retrieves and presents Web content for end
users. User agents include Web browsers, media players, @@ Editors' Note: virtual worlds?? @@ and plug-ins
that help in retrieving, rendering and interacting with Web content. UAAG 2.0
specifies requirements that, if satisfied by user
agent developers, will lower barriers to accessibility.
Overview
Accessibility involves a wide range of disabilities. These include visual,
auditory, physical, speech, cognitive, language, learning, neurological
disabilities, and disabilities related to ageing. UAAG 2.0 emphasizes the goal
of ensuring that all users, including users with disabilities, have control
over their environment for accessing the Web. Key methods for achieving that
goal include:
- optional self-pacing
- configurability
- device independence
- interoperability
- direct support for both graphical and auditory output
- adherence to published conventions.
Some users have more than one disability, and the needs of different
disabilities may contradict. Thus, many of the requirements in UAAG 2.0 use
configuration to ensure that a functionality designed to improve accessibility
for one user does not interfere with accessibility for another. A default user
agent setting may be useful for one user but interfere with accessibility for
another, therefore UAAG 2.0 prefers configuration requirements rather than
requirements for default settings. For some content, a feature required by UAAG
2.0 may be ineffective or cause content to be less accessible, making it
imperative that the user be able to turn off the feature. To avoid overwhelming
users with an abundance of configuration options, UAAG 2.0 includes
requirements that promote documentation and ease of configuration.
UAAG 2.0 acknowledges the importance of author preferences. However,
requirements are included to override certain author preferences when the user
would not otherwise be able to access that content.
Some UAAG 2.0 requirements may have security implications, such as
communication through APIs, or allowing programmatic read and write access to
content and user interface control. UAAG 2.0
assumes that features required by UAAG 2.0 will be built on top of an
underlying security architecture. Consequently, unless permitted explicitly in
a success criterion, UAAG 2.0 grants no conformance exemptions based on
security issues.
The UAWG expects that software that satisfies the requirements of UAAG 2.0
will be more flexible, manageable, extensible, and beneficial for all users.
UAAG 2.0 Layers of Guidance
In order to meet the needs of different audiences using UAAG, several layers
of guidance are provided, including overall principles, general
guidelines, testable success criteria, and a explanatory
intent, examples and resource links.
Principles - At the top are five principles that
provide the foundation for accessible user agents. Principles 3, 4, and 5
are congruent to Web Content Accessibility Guidelines (WCAG) 2.0:
perceivable, operable, understandable. Principles 1 and 2 are
specific to user agents: comply with specifications and facilitate
programmatic access.
Guidelines - Under the principles are guidelines. The
guidelines provide the basic goals that authors should work toward in order
to make user agents more accessible to users with different disabilities.
The guidelines are not testable, but provide the framework and overall
objectives to help authors understand the success criteria and better
implement the techniques.
Success Criteria - For each guideline, testable
success criteria are provided to allow UAAG 2.0 to be used where
requirements and conformance testing are necessary such as in design
specification, purchasing, regulation, and contractual agreements. In order
to meet the needs of different groups and different situations, three
levels of conformance are defined: A (lowest), AA, and AAA (highest).
Additional information on UAAG levels can be found in the section on Conformance.
The principles, guidelines, and success criteria work together to provide
layers of guidance on how to make user agents more accessible. Developers are
encouraged to view and apply all layers that they are able to order to best
address the needs of the widest possible range of users.
Note that even user agents that conform at the highest level (AAA) may not
be accessible to individuals with all types, degrees, or combinations of
disability, particularly in the cognitive, language, and learning areas.
Developers are encouraged to seek relevant advice about current best practice
to ensure that their user agent is accessible as possible to this community.
UAAG 2.0 Supporting Documents
A separate document, entitled "Implementing User Agent Accessibility
Guidelines 2.0" (the "Implementing document" from here on) provides
suggestions and examples of how each success criteria might be satisfied. It
also includes references to other accessibility resources (such as
platform-specific software accessibility guidelines) that provide additional
information on how a user agent may satisfy each success criteria. The
techniques in the Implementing document are informative examples only. Other strategies
may be used or required to satisfy the success criteria. The
UAWG expects to update the Implementing document more
frequently than the current guidelines. Developers, W3C Working Groups, users,
and others are encouraged to contribute examples and resources.
Components of Web
Accessibility
Web accessibility depends on accessible user agents and accessible content.
Accessible content availability is greatly influenced by the accessibility of
the authoring tool. For an overview of how these components of Web development
and interaction work together, see:
Levels of
Conformance
User Agents may claim conformance to UAAG 2.0 at one of three conformance
levels. The level achieved depends on the level of success criteria satisfied.
The conformance levels are:
- UAAG 2.0 Conformance at Level "A"
The user agent satisfies all of the Level A success criteria.
- UAAG 2.0 Conformance at Level "Double-A"
The user agent satisfies all of the Level A and Level AA success
criteria.
- UAAG 2.0 Conformance at Level "Triple-A"
The user agent satisfies all of the success criteria.
A user agent is any software that retrieves, renders and facilitates
end-user interaction with Web content.
UAAG 2.0 Guidelines
PRINCIPLE 1 (former
Principal 3): Ensure that the user interface and rendered content are
perceivable
Guideline 1.1(former 3.1) Provide access to alternative
content. [Implementing
1.1]
Summary: Let users see at a
glance which pieces of content have alternatives like alt text or longdesc
(1.1.1) and click on an item to see its available alternatives (1.1.3); they
can also choose at least one alternative like alt text to be always displayed
(1.1.2), but it's recommended that they also be able to specify a cascade, like
alt text if it's there, otherwise longdesc, otherwise, filename, etc.
1.1.1(former 3.1.2) Configurable Default Rendering:
The user can specify which types of alternative content to render by
default. (Level A)
1.1.2(former 3.1.3) Browse and Render: When a
rendered element has alternative content, the user can
render alternatives according to the following: (Level A)
- synchronized alternatives for time-based media (e.g., captions, audio
descriptions, sign language) can be rendered at the same time as their
associated audio tracks and visual tracks, and
- non-synchronized alternatives (e.g., short text alternatives, long
descriptions) can be rendered as replacements for the original rendered
content.
1.1.3(former 3.1.1) Identify Presence of Alternative
Content: The user can specify that alternative content indicators be
rendered along with elements that have alternative content (e.g. an icon to
indicate an image has a short text alternative). (Level A)
1.1.4(former 3.1.4) Rendering Alternative
(Enhanced): The user can specify the fallback order in which to render
alternative content. If the alternative content has a different height or width,
the user agent will reflow the viewport.(Level AA)
Guideline 1.2(former 3.4) Repair missing
content. [Implementing 3.4]
Summary: If the user
chooses, provide useful alternative content when the author didn't, such as
showing a filename in place of missing (3.4.1) or empty (3.4.2) alt text.
1.2.2(former 3.4.2) Repair Empty Alternatives:
The user can specify whether or not the user agent should generate and render
repair text (e.g. file name) when it recognizes that the author has provided empty alternative content. (Level AA)
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)
1.2.3 Repair Missing
Associations: The user can specify whether or not the user agent
should attempt to predict associations from author-specified presentation
attributes (i.e. position and appearance). (Level AAA)
Guideline 1.3(former 3.5) Provide highlighting for selection,
content focus, enabled elements, visited links. [Implementing
1.3]
Summary: Let users visually
distinguish selected, focused, and enabled items, and recently visited links
(1.3.1), with their choice of highighting options that at least include
foreground and background colors, and border color and thickness (1.3.2).
1.3.1(former 3.5.1) Highlighted items: The
user can specify that the following be highlighted so that each is uniquely
distinguished 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
- (d) presence of alternative content
- (e) recently visited links
1.3.2(former 3.5.2) Highlighting options: The
user can specify highlighting options that include at least: (Level A) 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) border (configurable color, style,
and thickness)
Guideline 1.4(former 3.6) Provide text
configuration. [Implementing 1.4]
Summary: Let users control
text font, color, and size (1.4.1), including whether all text should be the
shown the same size (1.4.2).
1.4.1(former 3.6.1) Configure Text: The user
can globally set the following characteristics of visually rendered text content, overriding any specified by the author or user agent defaults: (Level A)
- (a) text scale (i.e., the general size of
text) ,
- (b) font family, and
- (c) text color (i.e., foreground and
background).
1.4.2(former 3.6.2) Preserving Size
Distinctions: The user can specify whether or not distinctions in the
size of rendered text are preserved when that
text is rescaled (e.g. headers continue to be larger than body text). (Level A)
1.4.3(former 3.6.3) Option Range: The range of
options for each text characteristic includes at least (Level A):
- (a) the range offered by global
preference settings supported by the operating environment (i.e.
configured though the Control Panel or System) utility, or
- (b) if no such utility is available, the
range supported by the conventional APIs of the
operating environment for drawing text.
- Intent of Success Criterion 1.4.3(former 3.6.3):
Users need to be able to access the full range
of text characteristics that the operating system supports. The full range
may be determined by the operating environment (as determined by the
settings). If platform does not provide a range of text characteristics in
the control panel, then whatever text characteristics are supported by
drawing programs for that operating environment, must be made available to
the user.
- Examples of Success Criterion 1.4.3(former 3.6.3):
- Browser A supports only 3 font sizes:
Small, Medium, and Large. Lee, who has low vision, needs to use a font
size of 16 pt, which is between the medium and large sizes. Browser A
provides an option to override the 3 font sizes with the operating
system font range, so that Lee can select the 16 pt font size she
needs.
- Related Resources for Success Criterion 1.4.3(former 3.6.3):
Guideline 1.5(former 3.7) Provide volume
configuration. [Implementing
1.5]
Summary: Respect the user's
global audio volume settings (1.5.1), but also let users adjust the volume of
each audio track (1.5.2).
1.5.1(former 3.7.1) Global Volume: The user
can independently adjust the volume of all audio tracksthe user agent renders, relative to the global volume
level set through operating environment mechanisms.
However, the user agent may only override a global mute on explicit user
request and if the user has been cautioned about the implication. However, if audio is muted at the global level the user agent
should not override this unless the behavior is optional, not enabled by
default, and the user is cautioned as to its implications. (e.g. the alarm
clock application on a mobile device has an option to play the alarm even if
the system is muted, provided the check box is normally unchecked and is
accompanied by text cautioning the user about this behavior. (Level A) The user
can globally set volume of all audio tracks it renders (including a "mute"
setting) through available operating environment mechanisms.
(Level A)
1.5.2 (former 3.7.2)
Speech Volume: The user can adjust the volume of all audio tracks the user agent renders,
independently or relative to the volume level at the operating environment.
(Level A)
Guideline 1.6(former 3.8) Provide
synthesized speech configuration. [Implementing
1.6]
1.6.1(former 3.8.1) Speech Rate and Volume:
The user can specify the following for synthesized speech: (Level
A)
- speech rate and
- speech volume (independently of other
sources of audio).
1.6.2(former 3.8.2) Speech Pitch and Range:
The user can specify the following for synthesized speech: (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),
1.6.3(former 3.8.3) Advanced Speech
Characteristics: The user can specify all of the speech
characteristics offered by the speech synthesizer. (Level AAA)
1.6.4(former 3.8.4) Synthesized Speech
Features: For synthesized speech, the following features are provided:
(Level AA)
- (a) user-defined extensions to the
synthesized speech dictionary,
- (b) "spell-out", where text is spelled
one character at a time, or according to language-dependent pronunciation
rules,
- (c) at least two ways of speaking numerals:
one where numerals are spoken as individual digits and punctuation
(e.g. "one two zero three point five" for 1203.5 or "one comma two zero
three point five" for 1,203.5), and one where full numbers are spoken (e.g.
"one thousand, two hundred and three point five").
- (d) at least two ways of speaking
punctuation: one where punctuation is spoken literally, and one
where punctuation is rendered as natural pauses.
Guideline 1.7(former 3.9) Provide style sheets configuration.
[Implementing
1.7]
1.7.1(former 3.9.1) Author Style Sheets: If
one or more author style sheets are defined, the user
has the following options: (Level A)
- (a) select and apply one or more author
style sheets, or
- (b) turn off author style sheets.
1.7.2(former 3.9.2) User Style Sheets: If one
or more user style sheets are defined, the user
has the following options: (Level A)
- (a) select and apply one or more user
style sheets, or
- (b) turn off user style sheets.
Guideline 1.8(former 3.10) Help user to use
viewports and orient within viewports. [Implementing
1.8]
1.8.1(former 3.10.1) Highlight Viewport: The
viewport with the input focus
(including nested viewports and their containers) is highlighted, and the user
is able to customize attributes of the highlighted mechanism,
including, but not limited to, shape, size, stroke width, color, and blink rate
(if any). (Level A)
1.8.2(former 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 visible
portion of the viewport.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)
1.8.3(former 3.10.4) Resizable: The user has
the option to make graphical viewports resizable, within the limits of the
display, overriding any values specified by the author. (Level A)
1.8.4(former 3.10.5) Scrollbars: Graphical
viewports include scrollbars if the rendered content (including after user
preferences have been applied) extends beyond the viewport dimensions, overriding any values specified by the author.
(Level A)
1.8.5(former 3.10.6) Viewport History: For
user agents that implement a viewport history mechanism (e.g. "back" button),
the user can return to any state in the viewport history, restoring the prior
point of regard, input focus and selection.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)
1.8.6(former 3.10.7) Open on Request: The user
can specify whether or not top-level viewports (e.g. windows or tabs) open only
with an explicit user request or confirmation. 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)
1.8.7(former 3.10.8) Do Not Take Focus: If new
top-level viewports (e.g. windows or tabs)
are configured to open without explicit user request, the user can specify
whether or not top-level viewports take the active keyboard
focus when they open. 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)
1.8.8 (former 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)
1.8.9(former 3.10.10) Close Viewport: The user
can close any top-level viewports (e.g.
windows or tabs) . (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.
1.8.10(former 3.10.11) Same UI: The user can
specify that all top-level viewports (e.g.
windows or tabs) follow the current user interface configuration. The user has the option of having all top-level viewports (e.g. windows or tabs)
follow the same user interface configuration as the current or spawning
viewport. (Level AA)
1.8.11(former 3.10.12) Indicate Viewport Position:
The user can determine the viewport's position relative to the full
extent of the rendered content. (Level AA) 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)
Guideline 1.9(former
3.11) Provide an effective focus mechanism. [Implementing
1.9]
1.9.1(former 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)
1.9.2(former 3.11.2) Current Focus: The user
can make the keyboard focus of each viewport the active input focus. (Level A)
1.9.3(former 3.11.3) User Interface Focus: An
active input focus is provided.
(Level A)
1.9.4(former 3.11.4) Extensions Focusable: The
keyboard focus can navigate within
extensions to the user interface. (Level A)
1.9.5(former 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)
1.9.6(former 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)
1.9.7(former 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)
1.9.8(former 3.11.8) Bi-Directional: The user
can move the keyboard focus forward or backward to
any enabled element in the viewport. (Level A)
1.9.9(former 3.11.9) Sequential Navigation: If
the author has not specified a navigation order, the default is sequential navigation, in
document order. (Level A)
1.9.10(former 3.11.10) Only on User
Request: The user can specify that the
keyboard focus of a viewport only change
on explicit user request. (Level
A)
1.9.11(former 3.11.11) On Focus: The user can ensure that moving the keyboard focus to or from an enabled element does not cause the user
agent to take any further action. (Level A)
Guideline 1.10(former 3.12) Provide alternative views. [Implementing
1.10]
1.10.1(former 3.12.1) Text View: The user can
view all text source that is available to the user
agent. For content authored in text formats, a view of the text source is provided. (Level
AA)
1.10.2(former 3.12.2) Outline View: An "outline" view of rendered content is provided, composed
of labels for important structural elements (e.g. heading text, table titles,
form titles, and other labels that are part of the content). (Level AA)
Note: The constitutes the
important structural elements by the user (See 1.10.3). What constitutes a
label is defined by each markup language specification. For example, in HTML, a
heading (H1
-H6
) is a label for the section that
follows it, a CAPTION
is a label for a table, and the
title
attribute is a label for its element.
1.10.3(former 3.12.3) Configure Set of Important
Elements: The user can configure the set of important elements for the
hierarchical view, including by element type (e.g., headers). (Level AAA)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)
Guideline
1.11(former 3.13) Provide link information.
[Implementing 1.11]
1.11.1(former 3.13.1) Basic Link Information:
The following information is provided for each link (Level A):
- link element content,
- new viewport (whether the author has specified that the resource will open in
a new viewport)
1.11.2(former 3.13.2) Extended Link
Information: The following information is provided for each link
(Level AAA):
- link title,
- technology type (of the linked Web resource)
- internal/external: (whether the link is
internal to the resource e.g., the link is to a target in the same Web
page)
PRINCIPLE 2(former Principle
4). Ensure that the user interface is operable
2.1.1(former 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)
2.1.2(former 4.1.2) 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 A)
2.1.3(former 4.1.3) No Keyboard Trap
(Minimum): The user agent prevents keyboard traps as follows (Level
A):
- (a) in the UI: if keyboard focus can be
moved to a component using the keyboard, then focus can be moved away from
that component using standard sequential keyboard commands (e.g., TAB key)
- (b) in the rendered content: provides a
documented direct keyboard command that will always restore keyboard focus
to a known location (e.g., the address bar).
- (c) in the rendered content: provides a
documented direct keyboard command that will always move keyboard focus to
a subsequent focusable element
2.1.4(former 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)
2.1.5(former 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)
2.1.6(former
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)
2.1.7(former 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)
2.1.8(former 4.1.8) Keyboard Navigation: The
user can use the keyboard to navigate from group to group of focusable items
and to traverse forwards and backwards all of the focusable elements within
each group. Groups include, but are not limited to, toolbars, panels, and user
agent extensions. (Level AA)
2.1.9(former 2.1.9(former
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)
2.1.10(former 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)
2.1.11(former 4.1.11) User Override of
Accesskeys: The user can override any recognized author supplied
content keybinding (i.e. access key). The user must have an option to save the
override of user interface keyboard shortcuts so that the rebinding persists
beyond the current session. (Level AA)
2.1.12(former 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)
2.2.1(former 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)
2.2.2(former 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)
2.2.3(former 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)
2.3.1(former 4.3.1) Timing Adjustable: Where
time limits for user input are recognized and
controllable by the user agent, the user can extend the time limit. (Level
A)
2.3.2(former 5.1.2) Retrieval Progress: Show
the progress of content retrieval. (Level A)
Guideline 2.4(former
4.4) Help users avoid flashing that could cause seizures. [Implementing
2.4]
2.4.1(former 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)
2.4.2(former 4.4.2) Three Flashes: In its
default configuration, the user agent does not display any user interface
components or recognized content that flashes more than three times in any
one-second period (regardless of whether not the flash is below the general
flash and red flash thresholds). (Level AAA) [WCAG 2.0]
2.5.1(former 4.5.1) Change Preference Settings
The user can change settings that impact accessibility. (Level A)
2.5.2(former 4.5.2) Persistent Accessibility
Settings: User agent accessibility preference settings persist between
sessions. (Level A)
2.5.3(former 4.5.6) Restore all to default:
The user can restore all preference settings to default values. (Level A)
2.5.4(former 4.5.3) Multiple Sets of Preference
Settings: The user can save and retrieve multiple sets of user agent
preference settings. (Level AA)
2.5.5(former 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)
2.5.6(former 4.5.8) Change preference setting outside
the UI: The user can adjust preference settings from outside the user
agent user interface. (Level AA)
2.5.7(former 4.5.4) Portable Preference
Settings:The user can transfer preference settings across locations
onto a compatible system. (Level AAA)
2.5.8(former 4.5.5) Preferences Wizard: A
wizard helps the user to configure the accessibility-related user agent
preferences (at least). (Level AAA)
2.6.1(former 4.6.1) Find: The user can perform
a search within rendered content (e.g., not hidden with a style), including
text alternatives, for any sequence of characters from the document character set set.
(Level A)
2.6.2(former 4.6.2) Find Direction: The user
can search forward or backward from the focused location in content. The user
is notified of changes in search direction. The user is notified when the
search reaches the upper or lower extent of the content based on the search
direction. (Level A)
2.6.3(former 4.6.3) Match Found: When there is
a match, the user is alerted and the viewport moves so that the matched text
content is at least partially within it. The user can search for the next
instance of the text from the location of the match. (Level A)
2.6.4(former 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)
2.6.5(former 4.6.5) Advanced Find: The user
agent provides an accessible advanced search facility, with a case-sensitive
and case-insensitive search option, and the ability for the user to perform a
search within all content (including hidden content and captioning) for text
and text alternatives, for any sequence of characters from the document
character set. (Level AA)
2.7.1(former 4.7.7) Discover navigation and activation
keystrokes: Direct navigation and activation keystrokes are
discoverable both programmatically and via perceivable labels. (Level A)
2.7.2(former 4.7.3) Access Relationships: The
user can access explicitly-defined relationships based on the user's position
in content (e.g., show form control's label, show label's form control, show a
cell's table headers). (Level A)
2.7.3(former 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).
2.7.4(former 4.7.2) Direct navigation: The
user can navigate directly to important
(structural and operable) elements in rendered content. (Level A).
@@ Editor's note: Review the definition of "important
elements" @@
2.7.5(former 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)
2.7.6(former 4.7.5) Direct activation: The
user can move directly to and activate any operable elements in rendered
content. (Level AA)
2.7.7(former 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" @@
2.8.1(former 4.8.1) Configure Position: When
graphical user agent user interfaces
have toolbars, the user can add, remove and configure the position of user agent user interface
controls on those toolbars from a pre-defined set of controls. (Level
AAA)
2.8.2(former 4.8.2) Restore Default Toolbars:
The user can restore the default toolbar configuration. (Level
AAA)
2.9.1(former 4.9.1) Background Image Toggle:
The user has the global option to hide/show background images. (Level A)
2.9.2(former 4.9.2) Time-Based Media
Load-Only: The user can load time-based media content @@ Editors' Note: DEFINE@@ such that the first
frame is displayed (if video), but the content is not played until explicit user request. (Level
A)
2.9.3(former 4.9.3) Execution Placeholder: The
user can render a placeholder instead of
executable content that would normally be contained within an on-screen area
(e.g., Applet, Flash), until explicit user request to execute.
(Level A)
2.9.4(former 4.9.4) Execution Toggle: The user
can turn on/off the execution of executable content that would not normally be
contained within a particular area (e.g., Javascript). (Level A)
2.9.5(former 4.9.1) Playback Rate Adjustment for
Prerecorded Content: The user can adjust the playback rate of
prerecorded time-based media content, such that all of the following are true
(Level A):
- The user can adjust the playback rate of the time-based media tracks to between 50% and 250% of
real time.
- Speech whose playback rate has been adjusted by the user maintains pitch
in order to limit degradation of the speech quality.
- Audio and video tracks remain synchronized across this required range of
playback rates.
- The user agent provides a function that resets the playback rate to
normal (100%).
2.9.6(former 4.9.6) Stop/Pause/Resume
Multimedia: The user can stop, pause, and resume rendered audio and animation content (including video and
animated images) that last three or more seconds at their default playback
rate. (Level A)
2.9.7(former 4.9.6b) Navigate Multimedia: The
user can navigate along the timebase using a continuous scale, and by relative
time units within rendered audio and animations (including video and animated
images) that last three or more seconds at their default playback rate. (Level
A)
2.9.8(former 4.9.7) Semantic Navigation of Time-Based Media: The user can
navigate by semantic structure within the time-based media, such as by chapters
or scenes present in the media (AA).
2.9.9(former 4.9.8) Track Enable/Disable of Time-Based Media: During
time-based media playback, the user can determine which tracks are available
and select or deselect tracks. These selections may override global default
settings for captions, audio descriptions, etc.
2.9.10(former 4.9.9) Sizing Playback Viewport: User can adjust the size of
the time-based media up to the full height or width of the containing viewport.
In doing so, the user can preserve aspect ratio and to adjust the size of the
playback viewport to avoid cropping, within the scaling limitations imposed by
the media itself. (Level AA)
2.9.11(former 4.9.10) Scale and position alternative media tracks: User can
scale and position alternative media tracks independent of base video. (Level
AAA)
2.9.12(former 4.9.11) Adjust Playback Contrast and
Brightness: User can control the contrast and brightness of the
content within the playback viewport.
Applicability Notes:
The guideline only applies to images, animations, video, audio, etc. that
the user agent can recognize.
@@ Editors' Note: If the browser is playing the video
natively, there is only 1 user agent. In that case, it falls on the browser to
meet the UAAG spec. @@
@@ Editors' Note: If an author uses windows media
player inside the video element, the browser needs to map its native controls
to the embedded wmp controls, and provide access to all the controls. @@
@@ Editors' Note: User needs to be able to define
rendering parameters of playback at render-time. @@
Principle 3(former Principle 5): Ensure that the user
interface is understandable
Guideline 3.1(former 5.1) Help users avoid unnecessary
messages. [Implementing
3.1]
@@ Editors' Note: Add SC based on this note from IRC of
10 November 2010: We could consider adding to this section a recommendation
that messages have a checkbox that lets the user avoid getting the message
again. But I'm not sure how we could write it to have an appropriate scope,
that is only apply to messages where it's appropriate. AND when you do have
those check boxes, it's also useful to have something in the application's
settings that allows the user to reset those to their default, thus making all
the messages visible again.@@
3.1.2(former 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 or the user agent. (e.g., ignoring updating content marked "polite").
(Level AA)
3.2.1(former 5.2.1) Form Submission: The user
can specify whether or not recognized form submissions must be confirmed. The user can redefine keyboard shortcuts for submitting and
canceling recognized forms. (Level AA)
3.3.1(former 5.3.1) Accessible documentation:
The product documentation is available in a format
that conforms to WCAG 2.0 Level "A" or greater. (Level A)
3.3.2(former 5.3.2) Document Accessibility
Features: All user agent features
that benefit accessibility are documented. (Level A)@@ Editors' Note: write a definition of "benefit
accessibility" - as contributing to conforming to these guidelines or a feature
specifically added to improve accessibility @@
3.3.3(former 5.3.3) Changes Between Versions:
Changes to features that benefit accessibility since the previous user agent
release are documented. @@Editors' Note: Link to the
definition to benefit accessibility from previous 3.3.2 @@ Changes to features that affect accessibility since the
previous version of the user agent are documented. (Level AA)
3.3.4(former 5.3.4) Centralized View: There
is a centralized view of all features of the user agent that benefit
accessibility, in a dedicated section of the documentation.
(Level AAA) @@ Editors' Note: Link to new definition
of "benefit accessibility" @@
3.3.5(former 5.3.5) Context Sensitive
Help: There is context-sensitive help
on all user agent features that benefit accessibility. (Level AAA)
3.3.6(former 5.3.6) Appropriate Language: If
characteristics of the user agent involve producing an end user experience such
as speech, the user agent reacts appropriately to language changes.
Guideline 3.4(former 5.4) The user agent must behave in a
predictable fashion. [Implementing
3.4]
3.4.1(former 5.4.1) Control default focus: The
user agent provides a mechanism for setting global configuration of default
focus.
3.4.2(former 5.4.2) Unpredictable focus: The
user is informed when the user agent changes focus. The user agent provides a
global option to block uninitiated focus changes.
@@ Editors' Note: Missing: Greater ease in interpreting
security messaging. Should be cross-referenced with the security working group.
@@
PRINCIPLE 4(former
Principle 2): Facilitate programmatic access
Guideline
4.1(former 2.1) Facilitate programmatic access [Implementing 4.1]
Summary: Be compatible with
assistive technologies by supporting platform standards (4.1.1), including
providing information about all menus, buttons, dialogs, etc. (4.1.2, 4.1.6),
access to DOMs (4.1.4), and access to structural relationships and meanings,
such as what text or image labels a control or serves as a heading (4.1.5).
Where something can't be made accessible, provide an accessible alternative
version, such as a standard window in place of a customized window (4.1.3).
Make sure that that programmatic exchanges are quick and responsive (4.1.7).
4.1.2(former 2.1.2) Name, Role, State, Value,
Description: For all user interface components including user
interface, rendered content, generated
content, and alternative content, make available the name, role, state,
value, and description via a platform accessibility architecture.
(Level A)
4.1.3(former 2.1.3) Accessible Alternative: If
a component of the user agent user interface cannot be exposed through the
platform accessibility architecture, then provide an equivalent alternative
that is exposed through the platform accessibility architecture. (Level A)
4.1.4(former 2.1.4) Programmatic Availability of
DOMs: If the user agent implements one or more DOMs, they must
be made programmatically available to assistive technologies. (Level A)
4.1.5(former 2.1.5) Write Access: If a User
Agent keeps an internal representation of the user content in terms of element
structure, relationships between elements, element meaning, or some combination
thereof, it must expose this internal representation via an appropriate means
(normally by using the platform accessibility architecture or a
programmatically available DOM) (level A). If the user
can modify the state or value of a piece of content through the user interface (e.g., by checking a box
or editing a text area), the same degree of write access is available
programmatically. (Level A)
4.1.6(former 2.1.6) Properties: If any of the
following properties are supported by the accessibility platform architecture,
make the properties available to the accessibility platform architecture:
(Level A)
- the bounding dimensions and coordinates of rendered graphical objects
- font family of text
- font size of text
- foreground color of text
- background color of text.
- change state/value notifications
- selection
- highlighting
- input device focus
4.1.7(former 2.1.7) Timely Communication: For
APIs implemented to satisfy the requirements of UAAG 2.0, ensure that
programmatic exchanges proceed at a rate such that users do not perceive a
delay. (Level A)
PRINCIPLE 5(former
1): Comply with applicable specifications and conventions
Guideline 5.1(former 1.1) Ensure that
non-Web-based functionality is accessible.[Implementing
5.1]
Summary: The browser's own
menus, buttons, dialogs, etc. need to meet any accessibility standards for the
operating system.
5.1.1(former 1.1.1) Non-Web-Based 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.
(Level A)
1.1.2 Non-Web-Based
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)
1.1.3 Non-Web-Based
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)
Applicability Notes:
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
uploaders).
Guideline 5.2(former 1.2) Ensure that Web-based functionality
is accessible. [Implementing
5.2]
Summary: When the browser's
menus, buttons, dialogs, etc. are authored in HTML or similar standards, they
need to meet W3C's Web Content Accessibility Guidelines.
5.2.1(former 1.2.1) Web-Based Accessible (Level A):
User agent user interfaces that are rendered using Web standard
technologies conform to WCAG Level "A". (Level A)
5.2.2(former 1.2.2) Web-Based Accessible (Level
AA): User agent user interfaces that are rendered using Web standard
technologies conform to WCAG Level "AA". (Level AA)
5.2.3(former 1.2.3) Web-Based Accessible (Level
AAA): User agent user interfaces that are rendered using Web standard
technologies conform to WCAG Level "AAA". (Level AAA)
Applicability Notes:
This guideline does not apply to non-Web-based user agent user interfaces,
but does include any parts of non-Web-based user agents that are Web-based
(e.g., help systems).
Summary: Implement the
accessibility features of all the technologies you're using, such as supporting
the platform's multitasking capabilities, HTML's alt attribute for images, and
document your implementation.
5.3.1(former 1.3.1) Accessibility Features:
Implement and cite in the conformance claim the accessibility features
of content and platform technology
specifications. Accessibility features are those that are either (Level A):
- identified as such in the specification or
- allow authors to satisfy a requirement of WCAG.
Summary: Render content
according to the technology specification, including accessibility features
(5.4.1), and let users choose how content types are handled, such as opening
embedded images, videos, or documents in separate applications or saving them
to disk (5.4.2, 5.4.3).
5.4.1(former 1.4.1) Follow Specifications:
Render content according to the technology specification, except where
it would actually harm overall accessibility. (Level A)
5.4.2(former 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)
5.4.3(former 1.4.3) Alternative content handlers:
The user has the ability to select content elements and have them
rendered in alternative viewers. (Level AA)
Applicability Note:
When a rendering requirement of another specification contradicts a
requirement of UAAG 2.0, the user agent may disregard the rendering requirement
of the other specification and still satisfy this guideline.
Conformance
This section is normative.
Conformance means that the user agent satisfies the success criteria defined
in the guidelines section. This conformance section describes conformance and
lists the conformance requirements.
Conformance
Requirements
In order for a Web page to conform to UAAG 2.0, one of the following levels
of conformance is met in full.
- Level A: For Level A conformance (the minimum level of conformance), the
user agent satisfies all the Level A Success Criteria.
- Level AA: For Level AA conformance, the user agent satisfies all the
Level A and Level AA Success Criteria.
- Level AAA: For Level AAA conformance, the user agent satisfies all the
Level A, Level AA and Level AAA Success Criteria.
Note 1: Although conformance can only be achieved at the stated levels,
developers are encouraged to report (in their claim) any progress toward
meeting success criteria from all levels beyond the achieved level of
conformance.
Conformance Claims
(Optional)
If a conformance claim is made, the conformance claim must meet the
following conditions and include the following information (user agents can
conform to UAAG 2.0 without making a claim):
Conditions
on Conformance Claims
- At least one version of the conformance claim must be published on the
web as a document meeting level "A" of WCAG 2.0. A suggested metadata
description for this document is "UAAG 2.0 Conformance Claim".
- Whenever the claimed conformance level is published (e.g., product
information website), the URI for the on-line published version of the
conformance claim must be included.
- The existence of a conformance claim does not imply that the W3C has
reviewed the claim or assured its validity.
- Claimants may be anyone (e.g., user agent developers, journalists, other
third parties).
- Claimants are solely responsible for the accuracy of their claims
(including claims that include products for which they are not responsible)
and keeping claims up to date.
- Claimants are encouraged to claim conformance to the most recent version
of the User Agent Accessibility Guidelines Recommendation.
Required Components of an UAAG 2.0
Conformance Claim
- Claimant name and affiliation.
- Date of the claim.
- Conformance level satisfied.
- User agent information: The name of the user agent and sufficient
additional information to specify the version (e.g., vendor name, version
number (or version range), required patches or updates, human language of
the user interface or documentation).
Note: If the user agent is a collection of software components (e.g., a
browser and extentions or plugins), then the name and version information
must be provided separately for each component, although the conformance
claim will treat them as a whole. As stated above, the Claimant has sole
responsibility for the conformance claim, not the developer of any of the
software components.
- Included Technologies: A list of the web content technologies (including
version numbers) rendered by the user agent that the Claimant is including
in the conformance claim. By including a web content technology, the
Claimant is claiming that the user agent meets the requirements of UAAG 2.0
during the rendering of web content using that web content technology.
Note 1: Web content technologies may be a combination of constituent web
content technologies. For example, an image technology (e.g., PNG) might be
listed together with a markup technology (e.g., HTML) since web content in
the markup technology is used make web content in the image technology
accessible (e.g., a PNG graph is made accessible using an HTML table).
- Excluded Technologies: A list of any web content technologies produced by
the 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
Conformance Claim
A description of how the UAAG 2.0 success criteria were met where this may
not be obvious.
"Progress
Towards Conformance" Statement
Developers of user agents that do not yet conform fully to a particular UAAG
2.0 conformance level are encouraged to publish a statement on progress towards
conformance. The progress statement is the same as a conformance claim except
an UAAG 2.0 conformance level that is being progressed towards, rather than one
already satisfied, and report progress on success criteria not yet met. Authors
of "Progress Towards Conformance" Statement are solely responsible for the
accuracy of their statements. Developers are encouraged to provide expected
timelines for meeting outstanding success criteria within the Statement.
Disclaimer
Neither W3C, WAI, nor UAWG take any responsibility for any aspect or result
of any UAAG 2.0 conformance claim that has not been published under the
authority of the W3C, WAI, or UAWG.
This glossary is normative.
- accelerator key
- see keyboard command
- activate
- To carry out the behaviors associated with an enabled element in the rendered
content or a component of the user agent user
interface.
- active input focus
- see focus
- active selection
- see focus
- alternative content
- Content that can
be used in place of default content that may not be universally
accessible. Alternative content fulfills the same purpose as the original
content. Examples include text alternatives for non-text content,
captions for audio, audio descriptions for video, sign language for
audio, media alternatives for time-based media. See WCAG for more information.
- alternative content
stack
- A set of alternative content items. The items
may be mutually exclusive (e.g., regular contrast graphic vs. high
contrast graphic) or non-exclusive (e.g., caption track that can play at
the same time as a sound track).
- animation
- Graphical content rendered to automatically change
over time, giving the user a visual perception of movement. Examples
include video, animated images, scrolling text, programmatic animation
(e.g., moving or replacing rendered objects).
-
- application
programming interface (API), (conventional input/output/device
API)
- An application programming interface (API) defines how
communication may take place between applications.
- assistive technology
- An assistive technology:
- relies on services (such as retrieving Web
resources and parsing markup) provided by one or more other
"host" user agents. Assistive technologies communicate data and
messages with host user agents by using and monitoring APIs.
- provides services beyond those offered by the host user agents to
meet the requirements of users with disabilities. Additional services
include alternative renderings (e.g., as synthesized speech or
magnified content), alternative input methods (e.g., voice),
additional navigation or orientation mechanisms, and content
transformations (e.g., to make tables more accessible).
Examples of assistive technologies that are important in the context
of UAAG 2.0 include the following:
- screen magnifiers, which are used by people with visual
disabilities to enlarge and change colors on the screen to improve
the visual readability of rendered text and images.
- screen readers, which are used by people who are blind or have
reading disabilities to read textual information through synthesized
speech or braille displays.
- voice recognition software, which are used by some people who have
physical disabilities to simulate the keyboard and mouse.
- alternative keyboards, which are used by some people with physical
disabilities to simulate the keyboard and mouse.
- alternative pointing devices, which are used by some people with
physical disabilities to simulate mouse pointing and button
activations.
- Beyond 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
disabilities.
- audio
- The technology of sound reproduction. Audio can be
created synthetically (including speech synthesis), streamed from a live
source (such as a radio broadcast), or recorded from real world
sounds.
-
- audio description - (described
video, video description or descriptive narration)
- An equivalent alternative that takes the form of narration added to the
audio to describe important visual details that
cannot be understood from the main soundtrack alone. Audio description of
video provides information about actions, characters, scene changes,
on-screen text, and other visual content. In standard audio description,
narration is added during existing pauses in dialogue. In extended audio
description, the video is paused so that there is time to add
additional description.
- authors
- The people who have worked either alone or collaboratively to create
the content (e.g. content authors, designers, programmers, publishers,
testers).
- author styles
- Style property
values that are set by the author as part of the content.
- background
images
- Images that are rendered on the base background.
- base
background
- The background of the content as a whole, such that no
content may be layered behind it. In graphics applications, the base
background is often referred to as the canvas.).
- blinking
text
- Text whose visual rendering alternates between visible and invisible at
any rate of change.
- captions (caption)
- An equivalent alternative that takes the form of text presented and
synchronized with time-based media to provide not only the
speech, but also non-speech information conveyed through sound, including
meaningful sound effects and identification of speakers. In some
countries, the term "subtitle" is used to refer to dialogue only and
"captions" is used as the term for dialogue plus sounds and speaker
identification. In other countries, "subtitle" (or its translation) is
used to refer to both. Open captions are captions that are
always rendered with a visual track; they cannot be turned off.
Closed captions are captions that may be turned on and off.
The captions requirements of UAAG 2.0 assume that the user agent can recognize the captions as such.
Note: Other terms that include the word "caption" may
have different meanings in UAAG 2.0. For instance, a "table caption" is a
title for the table, often positioned graphically above or below the
table. In UAAG 2.0, the intended meaning of "caption" will be clear from
context.
- collated text transcript
- A collated text transcript is a text equivalent of a movie or
other animation. It is the combination of the text
transcript of the audio track and the text equivalent
of the visual track. For example, a
collated text transcript typically includes segments of spoken dialogue
interspersed with text descriptions of the key visual elements of a
presentation (actions, body language, graphics, and scene changes). See
also the definitions of text
transcript and audio description. Collated
text transcripts are essential for people who are deaf-blind.
-
-
- content (web
content)
- Information and sensory experience to be communicated
to the user by means of a user agent, including code or markup that
defines the content's structure, presentation, and interactions [adapted
from WCAG 2.0]
empty
content (which may be alternative content) is
either a null value or an empty string (e.g., one that is zero characters
long). For instance, in HTML, alt=""
sets the value of the
alt
attribute to the empty string. In some markup languages,
an element may have empty content (e.g., the HR
element in
HTML).
- cursor
- see focus
- default
- see properties
- document character set
- The internal representation of data in the source
content by a user agent.
- document object, (Document Object Model, DOM)
- The Document Object Model is a platform- and
language-neutral interface that allows programs and scripts to
dynamically access and update the content, structure and style of
documents. The document can be further processed and the results of that
processing can be incorporated back into the presented page. This is an
overview of DOM-related materials here at W3C and around the web: http://www.w3.org/DOM/#what.
- document source, (text source)
- Text the user agent renders upon user request to view
the source of specific viewport content (e.g. selected content, frame,
page).
- documentation
- Any information that supports the use of a user agent.
This information may be found, for example, in manuals, installation
instructions, the help system, and tutorials. Documentation may be
distributed (e.g., as files installed as part of the installation, some
parts may be delivered on CD-ROM, others on the Web). See guideline 5.3 for information about
documentation.
- element, element type
- UAAG 2.0 uses the terms "element" and "element type"
primarily in the sense employed by the XML 1.0 specification ([XML], section
3): an element type is a syntactic construct of a document type
definition (DTD) for its application. This sense is also relevant to
structures defined by XML schemas. UAAG 2.0 also uses the term "element"
more generally to mean a type of content (such as video or sound) or a
logical construct (such as a header or list).
- empty content
- see content
- enabled element, disabled
element
- An element with associated
behaviors that can be activated through the user interface or through an
API. The
set of elements that a user agent enables is generally derived from, but
is not limited to, the set of elements defined by
implemented markup languages. A disabled element is a potentially enabled
element that is not currently available for activation (e.g., a "grayed
out" menu item).
- equivalent alternative
- Acceptable substitute content that a user may not be
able to access. An equivalent alternative fulfills essentially the same
function or purpose as the original content upon presentation:
- text alternative: text that is available via the operating environment
that is used in place of non-text content (e.g., text equivalents for
images, text transcripts for audio tracks, or collated text
transcripts for a movie). [from WCAG 2.0]
- full text alternative for synchronized media including any
interaction: document including correctly sequenced text descriptions
of all visual settings, actions, speakers, and non-speech sounds, and
transcript of all dialogue combined with a means of achieving any
outcomes that are achieved using interaction (if any) during the
synchronized media. [from WCAG
2.0]
- synchronized alternatives: present essential audio information
visually (i.e., captions) and essential video information in an
auditory manner (i.e., audio descriptions). [from ATAG 2.0]
- events and
scripting, event handler, event type
- User agents often perform a task when an event having
a particular "event type" occurs, including a user interface event, a
change to content, loading of content, or a request from the operating environment. Some
markup languages allow authors to specify that a script, called an event
handler, be executed when an event of a given type occurs. An
event handler is explicitly associated with an
element through scripting, markup or the DOM.
- explicit user request
- An interaction by the user through the user agent user
interface, the focus, or the selection. User
requests are made, for example, through user
agent user interface controls and keyboard commands. Some examples
of explicit user requests include when the user selects "New viewport,"
responds "yes" to a prompt in the user agent's user interface, configures
the user agent to behave in a certain way, or changes the selection or
focus with the keyboard or pointing device. Note: Users
can make errors when interacting with the user agent. For example, a user
may inadvertently respond "yes" to a prompt instead of "no." This type of
error is considered an explicit user request.
- focus (active input focus, active selection,
cursor, focus cursor, focusable element, highlight, inactive input focus,
inactive selection, input focus, keyboard focus, pointer, pointing device
focus, selection, split focus, text cursor)
Hierarchical Summary of some focus terms
- Input Focus (active/inactive)
- Keyboard Focus (active/inactive)
- Cursor (active/inactive)
- Focus cursor (active/inactive)
- Text cursor (active/inactive)
- Pointing device focus (active/inactive)
- active input focus
- The input focus location in the active
viewport. The active focus is in the active
viewport, while the inactive input focus is the inactive viewport. The active input focus is usually visibly
indicated. In UAAG 2.0 "active input focus" generally refers to the
active keyboard input focus. @@ Editors' Note:
this term is not used in the document other than the
glossary.@@
- active selection
- The selection that will currently be affected by a user command, as
opposed to selections in other viewports, called inactive selections,
which would not currently be affected by a user command. @@ Editors' Note: this term is not used in the
document other than the glossary.@@
- conform
- see support
- cursor
- Visual indicator showing where keyboard input will occur. There are two
types of cursors: focus cursor (e.g. the
dotted line around a button) and text
cursor (e.g. the flashing vertical bar in a text field, also called a
'caret'). Cursors are active when in the active viewport, and inactive
when in an inactive viewport.
- focus cursor
- Indicator that highlights a user interface
element to show that it has keyboard
focus, e.g. a dotted line around a button, or brightened title bar on
a window. There are two types of cursors: focus cursor (e.g. the dotted
line around a button) and text cursor (e.g. the flashing
vertical bar in a text field).
- focusable element
- Any element capable of having input
focus, e.g. link, text box, or menu item. In order to be accessible
and fully usable, every focusable element should take keyboard focus, and ideally would also
take pointer focus.
- highlight, highlighted, highlighting
- Emphasis indicated through the user interface. For example, user agents
highlight content that is selected,focused, or matched by a search
operation. Graphical highlight mechanisms include dotted boxes, changed
colors or fonts, underlining, magnification, and reverse video.
Synthesized speech highlight mechanisms include alterations of voice
pitch and volume ("speech prosody"). User interface items may also be
highlighted, for example a specific set of foreground and background
colors for the title bar of the active window. Content that is
highlighted may or may not be a selection.
- inactive input focus
- An input focus location in an inactive viewport such as a background
window or pane. The inactive input focus location will become the active
input focus location when input focus returns to that viewport. An
inactive input focus may or may not be visibly indicated.
- inactive selection
- A selection that does not have the input
focus and thus does not take input events.
- input focus
- The place where input will occur if a viewport is active. Examples
include keyboard focus and pointing device focus. Input focus can also be
active (in the active viewport) or inactive (in an inactive viewport).
- keyboard focus
- The screen location where keyboard input will occur if a viewport is
active. Keyboard focus can be active (in the active viewport) or inactive
(in an inactive viewport).
- pointer
- Visual indicator showing where pointing device input will occur. The
indicator can be moved with a pointing device or emulator such as a
mouse, pen tablet, keyboard-based mouse emulator, speech-based mouse
commands, or 3-D wand. A pointing device click typically moves the input focus to the pointer location. The
indicator may change to reflect different states.When touch screens are
used, the "pointing device" is a combination of the touch screen and the
user's finger or stylus. On most systems there is no pointer (on-screen
visual indication) associated with this type of pointing device.
- pointing device focus
- The screen location where pointer input will occur if a viewport is
active. There can be multiple pointing device foci for example when using
a screen sharing utility there is typically one for the user's physical
mouse and one for the remote mouse. @@
Editors' Note: this term is not used in the document other than the
glossary.@@
- selection
- A user agent mechanism for identifying a (possibly empty) range of
content that will be the implicit source or target for subsequent
operations. The selection may be used for a variety of purposes,
including for cut-and-paste operations, to designate a specific element
in a document for the purposes of a query, and as an indication of point
of regard (e.g. the matched results of a search may be automatically
selected). The selection should be highlighted in a distinctive manner. On the
screen, the selection may be highlighted in a variety of ways, including
through colors, fonts, graphics, and magnification. When rendered using
synthesized speech, the selection may be highlighted through changes in
pitch, speed, or prosody.
- split focus
- A state when the user could be confused because the input focus is
separated from something it is usually linked to, such as being at a
different place than the selection or similar highlighting, or has been
scrolled outside of the visible portion of the viewport. @@ Editors' Note: this term is not used in the
document other than the glossary.@@
- text cursor
- Indicator showing where keyboard input will occur in text (e.g. the
flashing vertical bar in a text field, also called a caret).
- content focus, user interface focus, current focus
@@ Editor's Note: Need to find the hrefs to
these definitions and fix them. @@
- globally, global
configuration
- @@ Editors' Note: Needs to
be written@@
- graphical
- Information (e.g. text, colors, graphics, images, and
animations) rendered for visual consumption.
- highlight, highlighted,
highlighting
- see focus
- image
- Pictorial content that is static (i.e. not moving or
changing). See also the definition of animation.
- implement
- see support
- important elements
- This specification intentionally does not identify
which "important elements" must be navigable because this will vary by
specification. What constitutes "efficient navigation" may depend on a
number of factors as well, including the "shape" of content (e.g.,
sequential navigation of long lists is not efficient) and desired
granularity (e.g., among tables, then among the cells of a given table).
Refer to the Implementing document [Implementing UAAG 2.0] for
information about identifying and navigating important elements. @@ Editors' Note: Update links
- inactive input focus
- see focus
- inactive selection
- see focus
- informative (non-normative)
- see normative
- input configuration
- The set of bindings between user agent functionalities
and user interface input mechanisms
(e.g., menus, buttons, keyboard keys, and voice commands). The default
input configuration is the set of bindings the user finds after
installation of the software. Input configurations may be affected by
author-specified bindings (e.g., through the
accesskey
attribute of HTML 4 [HTML4]).
- input focus
- see focus
-
- keyboard command (keyboard
binding,keyboard shortcuts or accelerator
keys)
- Commands tied to particular UI controls or application functions,
allowing the user to navigate-to or activate them without traversing any
intervening controls (e.g., "ctrl"+"S" to save a document). It is
sometimes useful to distinguish keyboard commands that are associated
with controls that are rendered in the current context (e.g., "alt"+"D"
to move focus to the address bar) from those that may be able to activate
program functionality that is not associated with any currently rendered
controls (e.g., "F1" to open the Help system). Keyboard commands help
users accelerate their selections.
- keyboard focus
- see focus
- natural language
- Natural language is spoken, written, or signed human
language such as French, Japanese, and American Sign Language. On the
Web, the natural language of content may be specified by markup or
HTTP headers. Some examples include the
lang
attribute in HTML 4 ([HTML4] section 8.1), the xml:lang
attribute in XML 1.0 ([XML], section 2.12), the hreflang
attribute for links in HTML 4 ([HTML4],
section 12.1.5), the HTTP Content-Language header ([RFC2616], section 14.12)
and the Accept-Language request header ([RFC2616], section 14.4).
See also the definition of script.
- non-text content (non-text element, non-text equivalent)
- see text
- normative, informative (non-normative) [WCAG 2.0, ATAG
2.0]
- What is identified as "normative" is required for conformance (noting that one may conform in a
variety of well-defined ways to UAAG 2.0). What is identified as
"informative" (or, "non-normative") is never required for
conformance.
- notify
- To make the user aware of events or status changes.
Notifications can occur within the user agent user interface (e.g., a
status bar) or within the content display. Notifications may be passive
and not require user acknowledgment, or they may be presented in the form
of a prompt requesting a user response (e.g., a confirmation dialog).
- operating environment
- The term "operating environment" refers to the
environment that governs the user agent's operation, whether it is an
operating system or a programming language environment such as Java.
- override
- In UAAG 2.0, the term "override" means that one
configuration or behavior preference prevails over another. Generally,
the requirements of UAAG 2.0 involve user preferences prevailing over
author preferences and user agent default settings and behaviors.
Preferences may be multi-valued in general (e.g., the user prefers blue
over red or yellow), and include the special case of two values (e.g.,
turn on or off blinking text content).
- placeholder
- A placeholder is content generated by the user agent
to replace author-supplied content. A placeholder may be generated as the
result of a user preference (e.g., to not render images) or as repair content (e.g., when an
image cannot be found). A placeholder can be any type of content,
including text, images, and audio cues. A placeholder should identify the
technology of the replaced object. Placeholders appear in the alternative
content stack.
- platform accessibility
architecture
- A programmatic interface that is engineered to enhance communication
between mainstream software applications and assistive technologies
(e.g., MSAA, UI Automation, and IAccessible2 for Windows applications,
AXAPI for MacOSX applications, Gnome Accessibility Toolkit API for Gnome
applications, Java Access for Java applications). On some platforms it
may be conventional to enhance communication further via implementing a
DOM.
- plug-in [ATAG
2.0]
- A plug-in is a program that runs as part of the user
agent and that is not part of content. Users
generally choose to include or exclude plug-ins from their user
agents.
- point of regard
- The point of regard is the position in rendered content that the user
is presumed to be viewing. The dimensions of the point of regard may
vary. For example, it may be a point (e.g., a moment during an audio
rendering or a cursor position in a graphical rendering), or a range of
text (e.g., focused text), or a two-dimensional area (e.g., content
rendered through a two-dimensional graphical viewport). The point of
regard is almost always within the viewport, but it may exceed the
spatial or temporal dimensions of the
viewport (see the definition of rendered content for more
information about viewport dimensions). The point of regard may also
refer to a particular moment in time for content that changes over time
(e.g., an audio-only presentation). User agents may determine the point
of regard in a number of ways, including based on viewport position in
content, keyboard focus, and selection. The stability of the point
of regard is addressed by [@@ Editors' Note:
Need reference here@@].
- pointer
- see focus
- pointing device focus
- see focus
- profile
- A profile is a named and persistent representation of
user preferences that may be used to configure a user agent. Preferences
include input configurations, style preferences, and natural language
preferences. In operating environments with
distinct user accounts, profiles enable users to reconfigure software
quickly when they log on. Users may share their profiles with one
another. Platform-independent profiles are
useful for those who use the same user agent on different platforms.
[@@Editors' Note: Move this sentence to the appropriate
intent.]
- prompt [ATAG
2.0]
- Any user-agent-initiated request for a decision or piece of information
from a user.
- properties, values, and
defaults
- A user agent renders a document by applying formatting
algorithms and style information to the document's elements. Formatting
depends on a number of factors, including where the document is rendered
(e.g. on screen, on paper, through loudspeakers, on a braille display, on
a mobile device). Style information (e.g., fonts, colors, synthesized
speech prosody) may come from the elements themselves (e.g., certain font
and phrase elements in HTML), from style sheets, or from user agent
settings. For the purposes of these guidelines, each formatting or style
option is governed by a property and each property may take one value
from a set of legal values. Generally in UAAG 2.0, the term "property"
has the meaning defined in CSS 2 ([CSS2], section 3). A reference
to "styles" in UAAG 2.0 means a set of style-related properties. The
value given to a property by a user agent at installation is the
property's default
value.
- recognize
- Authors encode information in many ways, including in
markup languages, style sheet languages, scripting languages, and
protocols. When the information is encoded in a manner that allows the
user agent to process it with certainty, the user agent can "recognize"
the information. For instance, HTML allows authors to specify a heading
with the
H1
element, so a user agent that implements HTML
can recognize that content as a heading. If the author creates a heading
using a visual effect alone (e.g., just by increasing the font size),
then the author has encoded the heading in a manner that does not allow
the user agent to recognize it as a heading. Some requirements of UAAG
2.0 depend on content roles, content relationships, timing relationships,
and other information supplied by the author. These requirements only
apply when the author has encoded that information in a manner that the
user agent can recognize. See the section on conformance for more information about
applicability. User agents will rely heavily on information that the
author has encoded in a markup language or style sheet language.
Behaviors, style, meaning encoded in a script, and markup in
an unfamiliar XML namespace may not be recognized by the user agent as
easily or at all.
- rendered content, rendered
text
- Rendered content is the part of content that the user agent makes
available to the user's senses of sight and hearing (and only those
senses for the purposes of UAAG 2.0). Any content that causes an effect
that may be perceived through these senses constitutes rendered content.
This includes text characters, images, style sheets, scripts, and any
other content that, once processed, may be perceived through sight and
hearing.
- The term "rendered text" refers to text
content that is rendered in a way that communicates information about the
characters themselves, whether visually or as synthesized speech.
- In the context of UAAG 2.0, invisible
content is content that is not rendered but that may influence
the graphical rendering (i.e. layout) of other content. Similarly, silent
content is content that is not rendered but that may influence
the audio rendering of other content. Neither invisible nor silent
content is considered rendered content.
- repair content, repair text
- Content generated by the user agent to correct an
error condition. "Repair text" refers to the text portion of repair
content. Error conditions that may lead to the generation of repair
content include:
- Erroneous or incomplete content (e.g., ill-formed markup, invalid
markup, or missing alternative content that
is required by format specification);
- Missing resources for handling or rendering content (e.g., the user
agent lacks a font family to display some characters, or the user
agent does not implement a particular scripting language).
UAAG 2.0 does not require user agents to include repair content in the
document object. Repair content
inserted in the document object should conform to the Web Content
Accessibility Guidelines 1.0 [WCAG10]. For more
information about repair techniques for Web content and software, refer
to "Techniques for Authoring Tool Accessibility Guidelines 1.0" [ATAG10-TECHS].
- script
- In UAAG 2.0, the term "script" almost always refers to
a scripting (programming) language used to create dynamic Web content.
However, in guidelines referring to the written (natural) language of
content, the term "script" is used as in Unicode [UNICODE] to mean "A
collection of symbols used to represent textual information in one or
more writing systems."
- Information encoded in (programming) scripts may be
difficult for a user agent to recognize. For
instance, a user agent is not expected to recognize that, when executed,
a script will calculate a factorial. The user agent will be able to
recognize some information in a script by virtue of implementing the
scripting language or a known program library (e.g., the user agent is
expected to recognize when a script will open a viewport or retrieve a
resource from the Web).
- selection, current
selection
- see focus
- serial access, sequential navigation
- One-dimensional
access to rendered content. Some examples of serial access include
listening to an audio stream or watching a video (both of which involve
one temporal dimension), or reading a series of lines of braille one line
at a time (one spatial dimension). Many users with blindness have serial
access to content rendered as audio, synthesized speech, or lines of
braille.
The expression "sequential navigation" refers to navigation through an
ordered set of items (e.g., the enabled
elements in a document, a sequence of lines or pages, or a sequence
of menu options). Sequential navigation implies that the user cannot skip
directly from one member of the set to another, in contrast to direct or
structured navigation. Users with blindness or some users with a physical
disability may navigate content sequentially (e.g., by navigating through
links, one by one, in a graphical viewport with or without the aid of an
assistive technology). Sequential navigation is important to users who
cannot scan rendered content visually for context and also benefits users
unfamiliar with content. The increments of sequential navigation may be
determined by a number of factors, including element type (e.g., links
only), content structure (e.g., navigation from heading to heading), and
the current navigation context (e.g., having navigated to a table, allow
navigation among the table cells).
Users with serial access to content or who navigate sequentially may
require more time to access content than users who use direct or
structured navigation.
- support, implement, conform
- Support, implement, and conform all refer to what a
developer has designed a user agent to do, but they represent different
degrees of specificity. A user agent "supports" general classes of
objects, such as "images" or "Japanese." A user agent "implements" a
specification (e.g., the PNG and SVG image format specifications or a
particular scripting language), or an API
(e.g., the DOM API) when it has been programmed to follow all or part of
a specification. A user agent "conforms to" a specification when it
implements the specification and satisfies its conformance
criteria.
- synchronize
- The act of time-coordinating two or more presentation
components (e.g., a visual track with captions, or
several tracks in a multimedia presentation). For Web content developers,
the requirement to synchronize means to provide the data that will permit
sensible time-coordinated rendering by a user agent. For example, Web
content developers can ensure that the segments of caption text are
neither too long nor too short, and that they map to segments of the
visual track that are appropriate in length. For user agent developers,
the requirement to synchronize means to present the content in a sensible
time-coordinated fashion under a wide range of circumstances including
technology constraints (e.g., small text-only displays), user limitations
(e.g. slow reading speeds, large font sizes, high need for review or
repeat functions), and content that is sub-optimal in terms of
accessibility.
- technology (web content
technology) [WCAG 2.0, ATAG
2.0]
- A mechanism for encoding instructions to be rendered, played or
executed by user agents. Web Content
technologies may include markup languages, data formats, or programming
languages that authors may use alone or in
combination to create end-user experiences that range from static Web
pages to multimedia presentations to dynamic Web applications. Some
common examples of Web content technologies include HTML, CSS, SVG, PNG,
PDF, Flash, and JavaScript.
- text (text
content, non-text content, text element,
non-text element, text equivalent, non-text
equivalent )
- Text used by itself refers to a sequence of characters
from a markup language's document character set.
Refer to the "Character Model for the World Wide Web" [CHARMOD] for more
information about text and characters. Note: 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.
Atext
element adds text characters to either content or the user
interface. Both in the Web Content Accessibility Guidelines 2.0
[WCAG20] and in UAAG 2.0,
text elements are presumed to produce text that can be understood when
rendered visually, as synthesized speech, or as Braille. Such text
elements benefit at least these three groups of users:
- visually-displayed text benefits users who are deaf and adept in
reading visually-displayed text;
- synthesized speech benefits users who are blind and adept in use of
synthesized speech;
- braille benefits users who are blind, and possibly deaf-blind, and
adept at reading braille.
A text element may consist of both text and non-text data. For
instance, a text element may contain markup for style (e.g., font size or
color), structure (e.g., heading levels), and other semantics. The
essential function of the text element should be retained even if style
information happens to be lost in rendering. A user agent may have to
process a text element in order to have access to the text characters.
For instance, a text element may consist of markup, it may be encrypted
or compressed, or it may include embedded text in a binary format (e.g.,
JPEG).
Text
content is content that is composed of one or more text
elements. A text
equivalent (whether in content or the user interface) is an equivalent composed of
one or more text elements. Authors generally provide text equivalents for
content by using the alternative content
mechanisms of a specification.
A non-text element is an element
(in content or the user interface) that does not have the qualities of a
text element. Non-text content is composed of
one or more non-text elements. A non-text equivalent (whether in
content or the user interface) is an equivalent composed of
one or more non-text elements.
- text decoration
- Any stylistic effect that the user agent may apply to
visually rendered text that does not affect
the layout of the document (i.e., does not require reformatting when
applied or removed). Text decoration mechanisms include underline,
overline, and strike-through.
- text
format
- Any media object given an Internet media type of
"text" (e.g., "text/plain", "text/html", or "text/*") as defined in RFC
2046 [RFC2046], section 4.1, or
any media object identified by Internet media type to be an XML document
(as defined in [XML], section 2) or SGML
application. Refer, for example, to Internet media types defined in "XML
Media Types" [RFC3023].
- text transcript
- A text equivalent of audio information (e.g., an
audio-only presentation or the audio track
of a movie or other animation). A texr transcript provides text for both
spoken words and non-spoken sounds such as sound effects. Text
transcripts make audio information accessible to people who have hearing
disabilities and to people who cannot play the audio. Text transcripts
are usually created by hand but may be generated on the fly (e.g., by
voice-to-text converters). See also the definitions of captions and collated text
transcripts.
- track (audio track or visual track)
- Content rendered as sound through an
audio viewport. The audio track may be all or
part of the audio portion presentation (e.g., each instrument may have a
track, or each stereo channel may have a track). Also see definition of
visual track
- user agent
- A user agent is any software that retrieves, renders
and facilitates end user interaction with Web content.
- user agent default styles
- User agent default styles are style property
values applied in the absence of any author or user styles. Some
markup languages specify a default rendering for content in that markup
language; others do not. For example, XML 1.0 [XML] does not
specify default styles for XML documents. HTML 4
[HTML4] does not specify
default styles for HTML documents, but the CSS 2 [CSS2]
specification suggests a sample
default style sheet for HTML 4 based on current practice.
- user interface, user interface
control
- For the purposes of UAAG 2.0, user interface includes
both:
- the user agent user
interface, i.e., the controls (e.g., menus, buttons,
prompts, and other components for input and output) and mechanisms
(e.g., selection and focus) provided by the user agent ("out of the
box") that are not created by content.
- the "content user interface," i.e., the enabled elements that are
part of content, such as form controls, links, and applets.
The document distinguishes them only where required for clarity. For more
information, see the section on requirements for content, for user agent
features, or both @@.
The term "user interface control" refers to a component of the user
agent user interface or the content user interface, distinguished where
necessary.
- user
styles
- User styles are style property
values that come from user interface settings, user style sheets, or
other user interactions.
- values
- see properties
- view, viewport
- The user agent renders
content through one or more viewports. Viewports include windows,
frames, pieces of paper, loudspeakers, and virtual magnifying glasses. A
viewport may contain another viewport (e.g., nested frames). User agent user interface
controls such as prompts, menus, and alerts are not viewports.
Graphical and tactile viewports have two spatial dimensions. A viewport may also
have temporal dimensions, for instance when audio, speech, animations,
and movies are rendered. When the dimensions (spatial or temporal) of
rendered content exceed the dimensions of the viewport, the user agent
provides mechanisms such as scroll bars and advance and rewind controls
so that the user can access the rendered content "outside" the viewport.
Examples include: when the user can only view a portion of a large
document through a small graphical viewport, or when audio content has
already been played.
When several viewports coexist, only one has the current focus at a given moment.
This viewport is highlighted to make it stand out.
User agents may render the same content in a variety of ways; each
rendering is called a view. For instance, a user agent may allow
users to view an entire document or just a list of the document's
headers. These are two different views of the document.
top-level viewports are viewports
that are not contained within other user agent viewports.
- visual-only presentation
- A visual-only presentation is content consisting
exclusively of one or more visual
tracks presented concurrently or in series. A silent movie is an
example of a visual-only presentation.
- visual track
- A visual object is content rendered through a
graphical viewport. Visual objects include
graphics, text, and visual portions of movies and other animations. A
visual track is a visual object that is intended as a whole or partial
presentation. A visual track does not necessarily correspond to a single
physical object or software object.
- voice browser
- From "Introduction and Overview of W3C Speech
Interface Framework" [VOICEBROWSER]: "A
voice browser is a device (hardware and software) that interprets voice
markup languages to generate voice output, interpret voice input, and
possibly accept and produce other modalities of input and output."
- web resource
- Anything that can be identified by a Uniform Resource Identifier
(URI).
Appendix B: How to refer to
UAAG 2.0 from other documents
This section is informative.
There are two recommended ways to refer to the "User Agent Accessibility
Guidelines 2.0" (and to W3C documents in general):
- References to a specific version of "User Agent Accessibility Guidelines
2.0." For example, use the "this version" URI to refer
to the current document:
http://www.w3.org/TR/2010/WD-UAAG20-20100617/
- References to the latest version of "User Agent Accessibility Guidelines
2.0." Use the "latest version" URI to refer to the most recently published
document in the series:
http://www.w3.org/TR/UAAG20/.
In almost all cases, references (either by name or by link) should be to a
specific version of the document. W3C will make every effort to make this
document indefinitely available at its original address in its original form.
The top of this document includes the relevant catalog metadata for specific
references (including title, publication date, "this version"
URI, editors' names, and copyright information).
An XHTML 1.0 paragraph including a reference to this specific document might
be written:
<p>
<cite><a href="http://www.w3.org/TR/2010/WD-UAAG20-20100617/">
"User Agent Accessibility Guidelines 2.0,"</a></cite>
J. Allan, K. Ford, J. Spellman, eds.,
W3C Recommendation, http://www.w3.org/TR/ATAG20/.
The <a href="http://www.w3.org/TR/ATAG20/">latest version</a> of
this document is available at http://www.w3.org/TR/ATAG20/.</p>
For very general references to this document (where stability of content and
anchors is not required), it may be appropriate to refer to the latest version
of this document. Other sections of this document explain how to build a conformance claim.
Appendix C: References
This section is informative.
For the latest version of any W3C specification please
consult the list of W3C Technical Reports at
http://www.w3.org/TR/. Some documents listed below may have been superseded
since the publication of UAAG 2.0.
Note: In UAAG 2.0, bracketed labels such as "[WCAG20]" link
to the corresponding entries in this section. These labels are also identified
as references through markup.
- [CSS1]
- "Cascading
Style Sheets (CSS1) Level 1 Specification," B. Bos, H. Wium
Lie, eds., 17 December 1996, revised 11 January 1999. This W3C
Recommendation is http://www.w3.org/TR/1999/REC-CSS1-19990111.
- [CSS2]
- "Cascading
Style Sheets, level 2 (CSS2) Specification," B. Bos, H. Wium
Lie, C. Lilley, and I. Jacobs, eds., 12 May 1998. This W3C Recommendation
is http://www.w3.org/TR/1998/REC-CSS2-19980512/.
- [DOM2CORE]
- "Document
Object Model (DOM) Level 2 Core Specification," A. Le Hors, P.
Le Hégaret, L. Wood, G. Nicol, J. Robie, M. Champion, S. Byrne, eds., 13
November 2000. This W3C Recommendation is
http://www.w3.org/TR/2000/REC-DOM-Level-2-Core-20001113/.
- [DOM2STYLE]
- "Document
Object Model (DOM) Level 2 Style Specification," V. Apparao,
P. Le Hégaret, C. Wilson, eds., 13 November 2000. This W3C
Recommendation is
http://www.w3.org/TR/2000/REC-DOM-Level-2-Style-20001113/.
- [INFOSET]
- "XML
Information Set," J. Cowan and R. Tobin, eds., 24 October
2001. This W3C Recommendation is
http://www.w3.org/TR/2001/REC-xml-infoset-20011024/.
- [RFC2046]
- "Multipurpose
Internet Mail Extensions (MIME) Part Two: Media Types," N.
Freed, N. Borenstein, November 1996.
- [WCAG10]
- "Web
Content Accessibility Guidelines 1.0," W. Chisholm, G.
Vanderheiden, and I. Jacobs, eds., 5 May 1999. This W3C Recommendation is
http://www.w3.org/TR/1999/WAI-WEBCONTENT-19990505/.
- [XML]
- "Extensible
Markup Language (XML) 1.0 (Second Edition)," T. Bray, J.
Paoli, C.M. Sperberg-McQueen, eds., 6 October 2000. This W3C
Recommendation is http://www.w3.org/TR/2000/REC-xml-20001006.
- [AT1998]
- The Assistive Technology
Act of 1998.
- [ATAG10]
- "Authoring Tool
Accessibility Guidelines 1.0," J. Treviranus, C.
McCathieNevile, I. Jacobs, and J. Richards, eds., 3 February 2000. This
W3C Recommendation is http://www.w3.org/TR/2000/REC-ATAG10-20000203/.
- [ATAG10-TECHS]
- "Techniques
for Authoring Tool Accessibility Guidelines 1.0," J.
Treviranus, C. McCathieNevile, J. Richards, eds., 29 Oct 2002. This W3C
Note is http://www.w3.org/TR/2002/NOTE-ATAG10-TECHS-20021029/.
- [CHARMOD]
- "Character Model
for the World Wide Web," M. Dürst and F. Yergeau, eds., 30
April 2002. This W3C Working Draft is
http://www.w3.org/TR/2002/WD-charmod-20020430/. The latest version is available at
http://www.w3.org/TR/charmod/.
- [DOM2HTML]
- "Document
Object Model (DOM) Level 2 HTML Specification," J. Stenback,
P. Le Hégaret, A. Le Hors, eds., 8 November 2002. This W3C Proposed
Recommendation is
http://www.w3.org/TR/2002/PR-DOM-Level-2-HTML-20021108/. The latest version is
available at http://www.w3.org/TR/DOM-Level-2-HTML/.
- [HTML4]
- "HTML
4.01 Recommendation," D. Raggett, A. Le Hors, and I. Jacobs,
eds., 24 December 1999. This W3C Recommendation is
http://www.w3.org/TR/1999/REC-html401-19991224/.
- [RFC2616]
- "Hypertext Transfer
Protocol — HTTP/1.1," J. Gettys, J. Mogul, H. Frystyk, L.
Masinter, P. Leach, T. Berners-Lee, June 1999.
- [RFC3023]
- "XML Media
Types," M. Murata, S. St. Laurent, D. Kohn, January 2001.
- [SMIL]
- "Synchronized
Multimedia Integration Language (SMIL) 1.0 Specification," P.
Hoschka, ed., 15 June 1998. This W3C Recommendation is
http://www.w3.org/TR/1998/REC-smil-19980615/.
- [SMIL20]
- "Synchronized
Multimedia Integration Language (SMIL 2.0) Specification," J.
Ayars, et al., eds., 7 August 2001. This W3C Recommendation is
http://www.w3.org/TR/2001/REC-smil20-20010807/.
- [SVG]
- "Scalable
Vector Graphics (SVG) 1.0 Specification," J. Ferraiolo, ed., 4
September 2001. This W3C Recommendation is
http://www.w3.org/TR/2001/REC-SVG-20010904/.
- [UAAG10]
- "User Agent
Accessibility Guidelines 1.0," I. Jacobs, J. Gunderson, E. Hansen,
eds.17 December 2002. This W3C Recommendation is available at
http://www.w3.org/TR/2002/REC-UAAG10-20021217/.
- [UAAG10-CHECKLIST]
- An appendix to UAAG 2.0 lists all of the checkpoints, sorted by
priority. The checklist is available in either tabular
form or list
form.
- [UAAG10-ICONS]
- Information about UAAG 1.0 conformance
icons and their usage is available at
http://www.w3.org/WAI/UAAG10-Conformance.
- [UAAG10-SUMMARY]
- An appendix to UAAG 2.0 provides a summary of the goals and structure of User Agent
Accessibility Guidelines 1.0.
- [UAAG10-TECHS]
- "Techniques for User
Agent Accessibility Guidelines 1.0," I. Jacobs, J. Gunderson,
E. Hansen, eds. The latest draft of the techniques document is available
at http://www.w3.org/TR/UAAG10-TECHS/.
- [UNICODE]
- "The Unicode
Standard, Version 3.2." This technical report of the Unicode Consortium is available at
http://www.unicode.org/reports/tr28/. This is a revision of "The Unicode
Standard, Version 3.0," The Unicode Consortium, Addison-Wesley Developers
Press, 2000. ISBN 0-201-61633-5. Refer also to http://www.unicode.org/standard/versions/.
For information about character encodings, refer to Unicode Technical Report #17
"Character Encoding Model".
- [VOICEBROWSER]
- "Introduction
and Overview of W3C Speech Interface Framework," J. Larson, 4
December 2000. This W3C Working Draft is
http://www.w3.org/TR/2000/WD-voice-intro-20001204/. The latest version is available
at http://www.w3.org/TR/voice-intro/. UAAG 2.0 includes references to
additional W3C specifications about voice browser technology.
- [W3CPROCESS]
- "World
Wide Web Consortium Process Document," I. Jacobs ed. The 19
July 2001 version of the Process Document is
http://www.w3.org/Consortium/Process-20010719/. The latest version is
available at http://www.w3.org/Consortium/Process/.
- [WCAG10-TECHS]
- "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.
- [WEBCHAR]
- "Web
Characterization Terminology and Definitions Sheet," B.
Lavoie, H. F. Nielsen, eds., 24 May 1999. This is a W3C Working Draft
that defines some terms to establish a common understanding about key Web
concepts. This W3C Working Draft is
http://www.w3.org/1999/05/WCA-terms/01.
- [XAG10]
- "XML
Accessibility Guidelines 1.0," D. Dardailler, S. Palmer, C.
McCathieNevile, eds., 3 October 2001. This W3C Working Draft is
http://www.w3.org/TR/2002/WD-xag-20021003. The latest version is available at
http://www.w3.org/TR/xag.
- [XHTML10]
- "XHTML[tm] 1.0: The
Extensible HyperText Markup Language," S. Pemberton, et al.,
26 January 2000. This W3C Recommendation is
http://www.w3.org/TR/2000/REC-xhtml1-20000126/.
- [XMLDSIG]
- "XML-Signature
Syntax and Processing," D. Eastlake, J. Reagle, D. Solo, eds.,
12 February 2002. This W3C Recommendation is
http://www.w3.org/TR/2002/REC-xmldsig-core-20020212/.
- [XMLENC]
- "XML
Encryption Syntax and Processing," D. Eastlake, J. Reagle,
eds., 10 December 2002. This W3C Recommendation is
http://www.w3.org/TR/2002/REC-xmlenc-core-20021210/.
Appendix D:
Acknowledgments
Participants
active in the UAWG prior publication:
- Jim Allan (Co-Chair, Texas School for the Blind and Visually
Impaired)
- Alan Cantor (Invited Expert)
- Bim Egan (Royal National Institute of Blind People)
- Kelly Ford (Co-Chair, Microsoft)
- Mark Hakkinen (Invited Expert)
- Simon Harper (University of Manchester)
- Patrick Lauke (Opera Software)
- Greg Lowney (Invited Expert)
- Kimberly Patch (Invited Expert)
- Jan Richards (Adaptive Technology Resource Centre, University of
Toronto)
- Jeanne Spellman (W3C Staff Contact)
Other
previously active UAWG participants and other contributors to UAAG 2.0:
- Judy Brewer (W3C)
- Sean Hayes, Microsoft
- Dean Hudson, Apple
- Cathy Laws (IBM)
- Peter Parente (IBM)
- David Poehlman (Invited Expert)
- Simon Pieters, Opera Software
- Henny Swan (Opera)
- Gregory Rosmaita (Invited Expert)
- David Tseng (Apple)
UAAG 2.0 would not have been possible without the work of those who
contributed to UAAG 1.0.
This publication has been funded in part with Federal funds from the U.S.
Department of Education, National Institute on Disability and Rehabilitation
Research (NIDRR) under contract number ED-OSE-10-C-0067. The content of this
publication does not necessarily reflect the views or policies of the U.S.
Department of Education, nor does mention of trade names, commercial products,
or organizations imply endorsement by the U.S. Government.
Appendix E: Checklist
@@ Editors' Note: This section is still under
development@@
Appendix F:
Comparison of UAAG 1.0 guidelines to UAAG 2.0
@@ Editors' Note: This section is still under
development@@