This document proposes a framework for determining conformance
requirements for the checkpoints of the User Agent Accessibility
Guidelines 1.0.
This section describes the status of this document at the
time of its publication. Other documents may supersede this
document. The latest status of this document series is maintained
at the W3C.
This document is meant for review by the WAI User Agent Guidelines Working
Group. It represents no consensus of any kind and may be
updated, replaced or obsoleted by other documents at any time. It
is inappropriate to use this document reference material.
This document has been produced as part of the Web Accessibility Initiative. The goal
of the WAI User Agent Guidelines
Working Group is discussed in the Working Group
charter.
A list of current W3C Recommendations and other technical
documents can be found at
http://www.w3.org/TR.
Introduction
Readers of the User Agent Accessibility Guidelines
(UAAG) 1.0 should be able to tell when a user agent
has met the requirements of the document for a number of
reasons:
- The Guidelines should stand on their own.
- The Working Group must not be a central agency for interpreting
the Guidelines; the group won't scale well.
- The Working Group may cease to exist.
Some of the Working Group's goals for the UAAG 1.0 are difficult
to satisfy all at once:
- The guidelines should be general enough to cover a variety of
user agents, markup languages, and operating systems.
- The guidelines should not mandate a particular implementation
but should express functional requirements.
- The checkpoints must be specific.
This document presents a framework for categorizing the
checkpoints and explaining how one may determine that requirements
have been met. The document has been organized into three
sections:
- Checkpoints with minimal
requirements
- Checkpoints with expected
solutions
- Checkpoints with solutions identified by Working
Group
It should not be difficult to identify how to meet the
requirements of the checkpoints in sections 1 and 2. The
checkpoints in section 3 pose more problems and some may require
"arbitrary" requirements established by the Working Group.
Note. This document does not address the issue
of how to verify whether a user agent has actually met the
requirement. While the requirements of some of the checkpoints are
sufficiently clear, it may not be easy to assess conformance
without access to detailed technical information about a user
agent.
Note. Refer to
the proposal from Eric Hansen to incorporate minimal
requirements directly into checkpoints; the document should only
express minimal requirements.
For these checkpoints, it is possible to identify a minimal
requirement.
1.1 Meet logical minima
- Checkpoint 2.2 For
presentations that require user input within a specified time
interval, allow the user to configure the time interval (e.g., to
extend it or to cause the user agent to pause the presentation
automatically and await user input before proceeding).
Minimum: Pause.
Issue 293 asks for clarification of "presentation".
Refer to resolution of issue 293.
- Checkpoint 4.16
Allow the user to configure the user agent to limit the number of
open viewports. Minimum: Resolved
at 14
Sept teleconference with modifications to
proposal to fix checkpoint 4.17 (this checkpoint is 4.17 in 28 July
draft).
- Checkpoint 7.1 Allow the
user to navigate among viewports (including frames). Refer to
11 May teleconference, Minimum: Forward
sequential navigation.
- Checkpoint 7.3 Allow the
user to navigate all active elements. Refer to
11 May teleconference, Minimum: Forward
sequential navigation.
- Checkpoint 7.4 Allow the
user to choose to navigate only active elements. Refer to
11 May teleconference,Minimum: Forward and
reverse sequential navigation.
- Checkpoint 9.4 When
transferring content (e.g., a document, image, audio, video, etc.)
indicate what proportion of the content has been transferred and
whether the transfer has stalled. Deleted
per 10
August teleconf (refer to
issue 305).
- Checkpoint 9.5 Indicate the
relative position of the viewport in rendered content (e.g., the
percentage of an audio or video clip that has been played, the
percentage of a Web page that has been viewed, etc.). Resolved 3
August to include horizontal as part of position and to say
"proportion, not percentage" per
proposal from Ian. (issue
306).
1.2 Allow on/off control
Resolved: For all Guideline three checkpoints, the scope is
configuration, global, on-load. Refer to
proposed clarification on scope of configuration and
27 July resolution.
- Checkpoint 3.2 Allow the
user to turn on and off rendering of background audio.
- Open: Checkpoint 3.3 Allow
the user to turn on and off rendering of video.
- Checkpoint 3.4 Allow the
user to turn on and off rendering of audio.
- Checkpoint 3.1 Allow the
user to turn on and off rendering of background images.
- Checkpoint 3.5 Allow the
user to turn on and off animated or blinking text.
- Checkpoint 3.6 Allow the
user to turn on and off animations and blinking images.
- Checkpoint 3.7 Allow the
user to turn on and off support for scripts and applets.
- Checkpoint 3.9 Allow the
user to turn on and off rendering of images.
1.3 Require "all" of something
- Checkpoint 1.1 Ensure that
every functionality available through the user interface is also
available through every input API implemented by the user
agent.
- Checkpoint 1.2 Use the
standard input and output device APIs of the operating system.
- Checkpoint 1.3 Implement the
standard keyboard API of the operating system and ensure that every
functionality available through the user interface is available
through this API.
- Checkpoint 1.4 Ensure that
the user can interact with all active elements in a
device-independent manner.
- Checkpoint 1.5 Ensure every
non-text message (e.g., prompt, alert, notification, etc.) that is
part of the user agent's user interface also has a text equivalent
in the user interface.
- Checkpoint 2.1 Make all
content available through the user interface.
- Checkpoint 11.2 Document all
user agent features that promote accessibility.
- Checkpoint 11.4 In a
dedicated section of the documentation, describe all features of
the user agent that promote accessibility.
- Checkpoint 11.5 In each
software release, document all changes that affect
accessibility.
1.4 Conform to specifications
- Checkpoint 4.7 Allow the
user to position text transcripts, collated text transcripts, and
captions on graphical displays. Minimum: Position
according to the range allowed to the author by specification.
- Checkpoint 5.1 Provide
programmatic read access to HTML and
XML content by conforming to the W3C Document Object
Model (DOM) Level
2 Core and HTML modules and exporting the
interfaces they define.
- Checkpoint 5.2 If the user
can modify HTML and XML content through the user
interface, provide the same functionality programmatically by
conforming to the W3C Document Object Model (DOM) Level 2 Core and
HTML modules and exporting the interfaces they
define.
- Checkpoint 5.7 Provide
programmatic access to Cascading Style Sheets
(CSS) by conforming to the W3C Document Object
Model (DOM) Level
2 CSS module and exporting the interfaces it
defines.
- Checkpoint 6.1 Implement the
accessibility features of supported specifications (markup
languages, style sheet languages, metadata languages, graphics
formats, etc.). Note: In UAAG 1.0, this is not a
relative priority checkpoint. Therefore, it is P1 to implement all
accessibility features. Resolved at
13 July teleconference that the set of things to implement is:
- Those things labeled in the spec as such.
- Those things in the specification which support WAI Guidelines
requirements.
Refer also to
proposal to add note about implementation of optional features that
may hurt accessibility.
- Checkpoint 6.2 Use and
conform to W3C Recommendations when they are available and
appropriate for a task.
- Checkpoint 8.1 Make
available to the user the author-specified purpose of each table
and the relationships among the table cells and headers. Editorial
change only required for checkpoint per
13 July teleconference.
1.5 No clarification required
For these checkpoints, the requirement should be apparent, and
the solution in the user interface must be accessible.
- Checkpoint 2.4 Allow the
user to specify that text transcripts, collated text transcripts,
captions, and auditory descriptions be rendered at the same time as
the associated auditory and visual tracks. Respect author-specified
synchronization cues during rendering.
- Checkpoint 2.6 When a text
equivalent for content is explicitly empty (i.e., an empty string),
render nothing.
- Checkpoint 2.7 For
author-identified but unsupported natural languages, allow the user
to request notification of language changes in content. Refer to
proposed minimum from Ian. Proposed minimum:
Indicate the language change in content. Refer to discussion at
20 July teleconference, which was followed by a number of
editorial proposals on the list including a
proposal from Ian on 2.7. Resolved at
31 August teleconference accept
proposal from Jon on 2.7 with edits.
- Checkpoint 4.6 Allow
the user to start, stop, pause, advance, and rewind audio, video,
and animations. Awaiting resolution of
issue 289 and
issue 297. Refer also to
issue
raised by Ian about rewind to the beginning.
Resolved at
12 Sept. teleconference to adopt
most of proposal
to clarify Guidelines 3 and 4.
- Checkpoint 4.12 Allow the
user to select from available author and user style sheets or to
ignore them.
- Checkpoint 4.15 Allow the
user to configure whether the current focus moves automatically to
a viewport that opens without an explicit request from the
user.
- Checkpoint 7.2 For
user agents that offer a browsing history mechanism, when the user
returns to a previous viewport, restore the point of regard in the
viewport. Resolved per
17 August declaration by the Chair.
- Checkpoint 7.5 Allow the
user to search for rendered text content, including rendered text
equivalents. Resolved per
13 July teleconference: Minimum
- You need to be able to start a forward search from a location
in content selected or focused by the user. [The default starting
point is the beginning of content.]
- When a match occurs, you need to be able to continue searching
forward from that location in content.
- Case-insensitive search option (when applicable to the text
language).
Resolved at
14
Sept teleconference
to adopt Ian
proposal about 7.5 with modifications (refer to minutes).
- Checkpoint 8.2 Indicate to
the user whether a link has been visited. Resolved at
27 July telconf: one mechanism in addition to color and font
styles. For CSS user agents, consider CSS pseudo-elements, which
allows user styling. Refer to
discussions about color / font requirements for and
configurability.
- Checkpoint 8.3 Indicate to
the user whether a link has been marked up to indicate that
following it will involve a fee. Same resolution as for 8.2
- Checkpoint 8.8 Implement
selection, content focus, and user interface focus mechanisms.
Resolved 3
August to clarify per
proposal from Ian.
- Checkpoint 9.1 Ensure that
when the selection or content focus changes, it is in a viewport
after the change.
- Checkpoint 9.2 Allow
configuration so the user is prompted to confirm any form
submission not caused by explicit activation of a form submit
control.
- Checkpoint 10.1 Provide
information to the user about current user preferences for input
configurations (e.g., keyboard or voice bindings).
- Checkpoint 10.3 Provide
information to the user about current author-specified input
configurations (e.g., keyboard bindings specified in HTML documents
with the "accesskey" attribute).
- Checkpoint 10.7 For the
configuration requirements of this document, allow the user to save
user preferences in a profile. Refer to
proposal by Eric Hansen that the minimal requirement be one
profile in addition to the default profile.
- Checkpoint 11.1 Provide a
version of the product documentation that conforms to the Web
Content Accessibility Guidelines 1.0 [[WCAG10]].
Refer to
24 August telconf and resolution of
issue 310.
- Checkpoint 11.3 Document the
default input configuration (e.g., default keyboard bindings).
For these checkpoints, user agents should follow conventions and
widespread practice.
2.1 Follow system conventions
- Checkpoint 5.3 For markup
languages other than HTML and XML, provide
programmatic access to content using standard APIs (e.g.,
platform-independent APIs and standard APIs for
the operating system).
- Checkpoint 5.4 Provide
programmatic read and write access to user agent user interface
controls using standard APIs (e.g., platform-independent APIs such
as the W3C DOM, standard APIs for the operating
system, and conventions for programming languages, plug-ins,
virtual machine environments, etc.)
- Checkpoint 5.5 Provide
programmatic notification of changes to content and user interface
controls (including selection, content focus, and user interface
focus).
- Checkpoint 5.8 Follow
operating system conventions that affect accessibility. In
particular, follow conventions for user interface design, keyboard
configuration, product installation, and documentation.
- Checkpoint 8.9 Provide a
mechanism for highlighting and identifying (through a standard
interface where available) the current viewport, selection, and
content focus.
- Checkpoint 8.10 Provide a
mechanism for highlighting and identifying active elements.
- Checkpoint 10.2 Avoid
default input configurations that interfere with operating system
accessibility conventions.
- Checkpoint 10.6 Follow
operating system conventions to indicate the input
configuration.
2.2 Define range according to convention / practice
Convention might be system convention or what CSS offers. User
agents are expected to implement what has already been widely
implemented.
- Checkpoint 4.1 Allow the
user to configure the size of text. Resolved at
27 July teleconf: Adopt
proposed clarification from Ian. Resolved
at 15 June teleconf that the range of values will be those
provided at the system level.
- Checkpoint 4.2 Allow the
user to configure font family. Refer to resolution for 4.1.
- Checkpoint 4.3 Allow the
user to configure foreground color. Refer to resolution for
4.1.
- Checkpoint 4.4 Allow the
user to configure background color. Refer to resolution for
4.1.
- Checkpoint 4.8 Allow the
user to configure the audio volume. Resolved per
13 July teleconf: Accept
proposal to split checkpoint and have requirements for synch'd
audio and synth speec independent control of volumes.
- Checkpoint 4.9 Allow the
user to configure synthesized speech playback rate. Resolved at
6 July teleconference: Provide access to the full rate of
speech rates available in the speech synthesizer, going down to
[120?] and up to [500?], increments of 10 wpm?. Words per minute
subsequently changed to 5% variations. Other notes: If aural
cascading style sheets are supported, support the ranges defined in
CSS2.
- Checkpoint 4.10 Allow the
user to configure synthesized speech volume. Resolved per
13 July teleconf: Accept
proposal to split checkpoint and have requirements for synch'd
audio and synth speec independent control of volumes.
- Checkpoint 4.11 Allow the
user to configure synthesized speech pitch, gender, and other
articulation characteristics. As for volume, resolved at
6 July teleconference: Provide access to the full range of
values.
- Checkpoint 4.13 Allow the
user to configure how the selection is highlighted (e.g.,
foreground and background color). Minimum Refer to
8.2 resolution.
- Checkpoint 4.14 Allow the
user to configure how the content focus is highlighted (e.g.,
foreground and background color). Minimum Refer to
8.2 resolution. Also, mechanism must allow user to distinguish
selection and focus.
- Checkpoint 9.3 Allow
the user to configure notification preferences for common types of
content and viewport changes. Refer to
comments and questions about 9.3 from Ian. Deleted per resolution
at 31
August teleconf.
For these checkpoints, the minimal requirement is not
obvious.
3.1 Working Group determines range
- Checkpoint 2.5 When the
author has not specified a text equivalent for content as required
by the markup language, make available other author-specified
information about the content (e.g., object type, file name, etc.).
From discussion at
9 May teleconference, Minimum: Make available
resource name and type information as text. This information is
available from HTTP headers (Content-Location or requested
resource's URI for name, Content-Type for type).
- Checkpoint 3.8 For automatic
content changes specified by the author (e.g., redirection and
content refresh), allow the user to slow the rate of change. At the
9 May teleconference, we discussed identifying two requirements
here: redirection and content refresh (action item to follow). If
the checkpoint is narrowed to those cases, then we agreed to this
Minimum: (1) Manual effectuation of the change (2)
Notification of the need to effect the change. (3) Need to be able
to query whether manual effectuation necessary.
- Checkpoint 4.5 Allow
the user to slow the presentation rate of audio, video, and
animations. Refer to
9 May teleconference and
11 May teleconference, Minimum:
- For a visual track (animation or movie): At least one setting
between 40% and 60% of the original speed.
- For a pre-recorded auditory track including stand-alone audio
presentations: At least one setting between 75% - 80% of the
original speed.
- For a synchronized multimedia presentation: For any visual
track that may be slowed from 100% to to 80% of its original speed,
need to synchronize visual and auditory tracks. Below 80%, the user
agent can drop out the auditory track.
Resolved at
12 Sept. teleconference to adopt
most of proposal
to clarify Guidelines 3 and 4.
- Open: Checkpoint 7.6 Allow the
user to navigate efficiently to and among important structural
elements identified by the author. Refer to
11 May teleconference, Minimum:
- For markup languages with known semantics, minimum is forward
sequential navigation to important structural elements.
- For other markup languages, minimum is forward sequential
navigation through the document object.
Per 3 August
teleconference, accept
proposal to list elements explicitly where known (e.g., HTML,
SMIL). Refer to
proposed list of elements.
Refer to objection
from Al Gilman.
- Checkpoint 7.7 Allow the
user to configure structured navigation. Refer to
11 May teleconference, Minimum:
- For markup languages with known semantics, allow inclusion and
exclusion of element types in the sequential navigation
sequence.
- Checkpoint 8.4 Make
available to the user an "outline" view of content, built from
structural elements (e.g., frames, headings, lists, forms, tables,
etc.). Refer to
11 May teleconference, Minimum: The outline
view is constructed from the set of navigable elements determined
by checkpoint 7.6.
- Checkpoint 8.5 Allow the
user to configure the outline view. Refer to
11 May teleconference, Minimum: The same
configurability as checkpoint 8.5; allow inclusion and exclusion of
element types in outline view. Note that where elements do not have
labels, the minimal label the user agent must generate is the
element type.
- Checkpoint 8.6 To
help the user decide whether to follow a link, make available link
information specified by the author and computed by the user agent.
Refer to
11 May teleconference, Minimum: Link content,
link title, whether the link is internal, whether the link has been
visited, whether it involves a fee, and hints on the content type,
size, and natural language of the linked resource.
Resolved per
17 August declaration by the Chair.
- Checkpoint 8.7 Allow the
user to configure what information about links to present.
Minimum: Allow the user to choose from among the minimal
requirements of checkpoint 8.6 (or whatever additional information
is provided). Deleted as a result of
3 August 2000 teleconf.
- Checkpoint 10.4 Allow the
user to change the input configuration. Resolved at
27 July teleconference (refer to those minutes for details;
based on a
proposal for 10.4.
- Checkpoint 10.5 Allow the
user to configure the user agent so that the user's preferred
one-step operations may be activated with a single input command
(e.g., key stroke, voice command, etc.). Resolved at
27 July teleconference (refer to those minutes for details;
based on a
proposal for 10.5 to be for the keyboard only.
- Checkpoint 10.9 For
graphical user interfaces, allow the user to configure the
arrangement of user agent user interface controls. Refer to
20 April teleconference and
1 June teleconference, Minimum:
- Allow the user to change the position of controls on a tool
bar.
- Allow the user to remove and restore controls from a predefined
set.
- Allow the user to restore default the menu and toolbar
settings.
3.2 Provide easy access
3.3 Suggest a sample implementation
- Checkpoint 5.6 Ensure that
programmatic exchanges proceed in a timely manner. Sample
implementation: The techniques document describes how to
allow in-process communication, which is a representative technique
of the type of performance expected.
Last modified: $Date: 2000/11/08 07:48:49 $