Draft Reformulation of Web Content Accessibility Guidelines
W3C Working Draft 12 July 2000
- This version:
- http://www.w3.org/WAI/GL/WCAG20/WD-WCAG20-20000713
- Latest version:
- http://www.w3.org/WAI/GL/WCAG20
- Author:
- Jason White, University of Melbourne
Status
This document is prepared by the W3C
Web Content Accessibility Guidelines Working Group (WCAG WG) to show how
more generalized (less HTML-specific) WCAG checkpoints might
read. This draft is not based on consensus of the working group nor
has it gone through W3C process thus it in no way supercedes the checkpoints
in WCAG 1.0. This draft derived from the following materials:
Based on feedback about the application of WCAG 1.0 to emerging XML
applications and other Web trends the WCAG WG wants to investigate how more
generalized checkpoints might read. Therefore, this draft has been
produced.
This is a draft document and may be updated, replaced, or obsoleted by
other documents at any time. It is inappropriate to use W3C Working Drafts as
reference material or to cite them as other than "work in progress". A list of
current W3C Recommendations and other technical documents can be found at http://www.w3.org/TR/.
Please send comments on this document to w3c-wai-gl@w3.org. The archives for this
list are publicly available.
Introduction
The following new terminology is proposed in this draft:
- 1: Principles
- These are the highest, most abstract general maxims of accessible
design, from which the concrete requirements are derived. In effect,
they serve as subject headings under which the guidelines are categorized. They correspond to what
were called "guidelines" in WCAG 1.0.
- 2: Guidelines.
- These requirements are more specific and detailed than the general principles; however, they are not specific to any
particular technology. Some of the requirements may be applicable only
to a certain range of protocols or data representations
(E.G. multimedia formats), but they are not restricted to
the features or capabilities that may appertain to any particular,
existing standard, specification or implementation. Guidelines in this sense sometimes correspond to
"checkpoints" in WCAG 1.0, but only in those instances
where the latter are expressed in general (rather than
technology-specific) terms.
- 3: Checkpoints [not shown in this draft].
- These are the technology-specific requirements, suitable for
implementation by a content designer or authoring tool, which have been
derived by applying the guidelines to a specific
technology, whether it be a communication protocol, software interface,
or a combination of markup and/or style languages. Checkpoints are
non-normative, in that there may exist other, equally effective means of
satisfying the requirements specified in the guidelines. However, proper application of the
checkpoints is deemed to constitute a correct and adequate
implementation of the guidelines. Stated differently, the checkpoints
operate as sufficient, but not as necessary conditions
for determining whether the guidelines have been followed.
Principles and Guidelines
Principle 1: Provide alternatives to auditory and visual
presentations
Guidelines
- Provide a textual equivalent for every non-text (auditory or graphical)
component of a web page or multimedia presentation.
- Until user agents can automatically read aloud the text equivalent of a
visual track, provide an auditory description of the important information
of the visual track of a multimedia presentation.
- For any time-based multimedia presentation (e.g., a movie
or animation), synchronize equivalent alternatives (e.g.,
captions or auditory descriptions of the visual track) with the
presentation.
Principle 2: Separate content and structure from presentation, and ensure
that significant structural or semantic distinctions are captured in explicit
markup.
Guidelines
- Use markup languages properly and in accordance with specification.
- Use style languages, where available, to control layout and
presentation.
- Where presentation is used to communicate distinctions of meaning or
structure within the content, ensure, if possible, that semantic markup is
also provided which conveys these distinctions equivalently. Note that the
semantic and presentational markup corresponding to a
document need not reside in the same file or logical resource; these
guidelines mandate only that both must exist and be available to the user
agent.
- Do not rely on presentation alone (E.G. colour or font
changes) to express semantic distinctions (this is a corollary of the
preceding guideline).
- Ensure that distinctions which are necessary or beneficial to the
rendering of the content in different media (E.G. auditory or
tactile) are reflected in the markup. For instance, use markup to identify
changes in the natural language of a document, or to distinguish fragments
of mathematical notation or computer program code from the surrounding
text.
Principle 3: Provide default presentations, while facilitating the
application of user-specified presentations
Guidelines
- Specify one or more default presentations of the content, for
example with style sheets, or by supplying pre-formatted versions which
can be selected via content negotiation or explicit user requests. Where
practicable, offer a variety of alternative presentations suited to
different output devices. For example, provide style sheets relevant to
high and low-resolution displays, printers and speech output systems.
- To facilitate the application of user-supplied transformations and style
rules, ensure that documents validate to the formal grammars of markup
languages which are defined in published specifications, and which support
the application of these guidelines.
- When using style languages which support a "cascade" of authors' and
users' preferences, ensure that style sheets are designed in such a way as
to operate gracefully if partially overridden by the user agent. For
example, specify lengths in relative rather than absolute units of
measure.
Principle 4: Design for ease of comprehension, browsing and
navigation
Guidelines
- Use a consistent style of presentation in which the structural and
semantic distinctions expressed in the markup, are associated with
appropriate formatting conventions that enhance the readability and
intelligibility of the content.
- Provide clear and consistent navigation mechanisms throughout a web
site.
- Supply an overview of the general organization of a site or of a
document which has been split into multiple, independent resources
(E.G. in a map or table of contents).
- Divide large blocks of information into more manageable groups where
natural and appropriate.
- If search functions are provided, enable different types of searches for
different skill levels and preferences.
- Place distinguishing information at the beginning of headings,
paragraphs, lists, etc.
- Use the clearest and simplest language appropriate for a site's
content.
- Supplement text with graphic or auditory presentations where they will
facilitate comprehension of the content.
- Use headings, labels and titles appropriately to identify structurally
significant divisions within the content. Note that in addition to full,
descriptive labels, it may also be appropriate, in designing complex
structures such as tables and forms, to provide abbreviated labels which
can be used when the content is rendered on small displays or via speech
output.
- Provide an overview or summary of highly structured materials, such as
tables.
- Define key terms, and provide expansions for abbreviations and acronyms,
which should be identified using appropriate markup.
Principle 5: Design user interfaces for device independence
Guidelines
These need to be reworked to take account of the separation between user
interface logic and presentation which is provided by X-Forms.
- Associate an explicit label with each user interface control.
- Ensure that user interface controls are grouped logically.
- Ensure that event handlers are device-independent.
- Design user interfaces to be compatible with assistive
technologies.
Principle 6: Compensate for older technologies and missing or incompletely
implemented features of user agents
Guidelines
- Make sure that web sites which use newer technologies transform
gracefully.
- Avoid causing content to blink or flicker.
- Avoid causing pages to be refreshed or updated automatically.
Any other interim measures which are considered to be of vital importance
may be included here.
Checkpoints without an obvious place in this scheme
Checkpoint 2.2 from WCAG 1.0 doesn't seem to fit:
2.2 Ensure that foreground and background color combinations provide
sufficient contrast when viewed by someone having color deficits or when
viewed on a black and white screen.
Most other checkpoints can be subsumed under the HTML/CSS
technology-specific checklists, or have been incorporated within the
generalized guidelines as presented above.
$Date: 2000/11/08 08:27:40 $