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Web Content Accessibility Guidelines: Implementation, Promotion, Future Development

Judy Brewer
Director, Web Accessibility Initiative
MIT/LCS, Cambridge, MA, USA
World Wide Web Consortium
Email: jbrewer@w3.org Website: http://www.w3.org/WAI

Daniel Dardailler
Project Manager, Web Accessibility Initiative
INRIA, Sophia-Antipolis, France
World Wide Web Consortium
Email: danield@w3.org 
Website: http://www.w3.org/WAI

This paper presents the World Wide Web Consortium (W3C) Web Content Accessibility Guidelines 1.0 (WCAG 1.0) and supporting resources, and discusses issues involved in promotion, implementation, and future development of Web content guidelines. It includes a brief overview of the guidelines, a discussion of use of the guidelines for site evaluation, site design, teaching of accessibility, and as the basis of the Authoring Tool Accessibility Guidelines; introduction of supporting materials including a demonstration reconstruction of an inaccessible site; on-line guidelines curriculum and technical reference notes. The session will discuss future issues for WAI guidelines development; and conclude with a discussion of guidelines promotion efforts and policy developments.

Brief Overview of the Web Content Accessibility Guidelines

The "Web Content Accessibility Guidelines 1.0" are a W3C specification providing guidance on accessibility of Web sites for people with disabilities. They have been developed by the W3C's Web Accessibility Initiative. The specification contains fourteen guidelines which are general principles of accessible design. Each guideline is associated with one or more checkpoints describing how to apply that guideline to particular features of Web pages. An appendix to the guidelines, "Checklist of Checkpoints for the Web Content Accessibility Guidelines 1.0" presents the checkpoints sorted by priority for easy reference. These guidelines not only make pages more accessible to people with disabilities, but also have the additional benefit of making pages more accessible to all users, or to users using different browsers or one of the emerging handheld or voice-based computers.

Each checkpoint is assigned one of three priority levels. Priority one is for checkpoints that a developer must satisfy otherwise some groups of people will be unable to access information on a site; priority two a developer should satisfy or else it will be very difficult to access information; priority three a developer may satisfy, otherwise some people will find it difficult to access information.

The specification defines three "conformance levels" to facilitate reference by other organizations. Conformance level "Single-A" includes priority one checkpoints; "Double-A" includes priority one and two; "Triple-A" includes priority one, two and three. For those whose pages follow the guidelines, logos are available which can be placed on their site to show conformance.

The guidelines address barriers in Web pages which people with physical, visual, hearing, and cognitive/neurological disabilities may encounter. Common accessibility problems on Web sites include: images without alternative text; lack of alternative text for imagemap hot-spots; misleading use of structural elements on pages; uncaptioned audio or undescribed video; lack of alternative information for users who cannot access frames or scripts; tables that are difficult to decipher when linearized; or sites with poor color contrast.

The following guidelines are explained in more detail in the Guidelines document:

  1. Provide equivalent alternatives to auditory and visual content.
  2. Don't rely on color alone.
  3. Use markup and style sheets and do so properly.
  4. Clarify natural language usage.
  5. Create tables that transform gracefully.
  6. Ensure that pages featuring new technologies transform gracefully.
  7. Ensure user control of time-sensitive content changes.
  8. Ensure direct accessibility of embedded user interfaces.
  9. Design for device-independence.
  10. Use interim solutions.
  11. Use W3C technologies and guidelines.
  12. Provide context and orientation information.
  13. Provide clear navigation mechanisms.
  14. Ensure that documents are clear and simple.
Using the Guidelines with Supporting Resources

The Web Content Accessibility Guidelines form the core of Web accessibility resources used for a variety of purposes. The session will briefly introduce and discuss the following resources, as well as future resources under development, and will invite suggestions for additional educational or outreach materials.

Reviewing Web site accessibility

The "Checklist of Checkpoints for Web Content Accessibility Guidelines 1.0" can be used as a prioritized checklist for reviewing Web site accessibility. The Checklist is organized with high-priority, lowest-complexity checkpoints first, and can be used as a manual review to identify what types of markup may present accessibility problems on different Web sites. The "Web Accessibility Report Tool" provides a way to report on accessibility of sites to Webmasters of those sites. The Checklist is primarily useful to identify problems on a site; if one wants to explore how to repair those, one would follow the Checklist's links to either the Guidelines document or the Techniques document.

Designing new Web sites

For new site design, the Guidelines provide an introduction to themes of accessible design, and a detailed explanation of requirements to ensure that a site is accessible to people with a variety of disabilities. The Techniques document provides additional implementation detail for any unfamiliar areas of document markup. Additional W3C technical reference Notes on HTML, CSS, and SMIL explain how to use the specific features of those languages to support accessibility.

Teaching Web site accessibility

While the Guidelines form the core reference material explaining requirements for Web accessibility, the Web Content Accessibility Guidelines Curriculum gives an on-line presentation complete with Web-based examples of each checkpoint in the Guidelines. It is suitable for use either as classroom or workshop presentation materials; or as on-line self-instruction materials. "How People with Disabilities Use the Web" provides general background on how various types of disabilities affect access to the Web, what barriers result, what assistive technologies are available, and scenarios of people using the Web with different accommodations.

Developing Authoring Tools

The Web Content Accessibility Guidelines form the basis for the Authoring Tool Accessibility Guidelines, which describe how to develop Web site authoring tools that promote the creation of accessible content. For example, the Web Content Accessibility Guidelines explain that equivalent alternatives are needed for audio elements on Web sites, and the Authoring Tool Accessibility Guidelines describe for tool developers how to ensure the creation of equivalent alternatives for audio -- in other words captions or transcripts -- by prompting for captions, alerting for missing information, and providing help files describing how to make captions.

Developing Evaluation Tools

The Web Content Accessibility Guidelines also form the basis of "accessibility checkers" and "retrofitting tools" by providing a consensus version of the guidelines against which to test Web sites. The document "Techniques for Evaluation and Implementation of Web Content Accessibility Guidelines" describe how to machine-test for each checkpoint in the guidelines, wherever machine-testing is feasible.

Reconstructing a Web site using WCAG 1.0

Some of the most common barriers to accessibility on the Web involve the use of bit-mapped text in images, lack of titles for frames, and use of cryptic text for hypertext links. WAI's demonstration "before & after accessibility reconstruction" shows a typically inaccessible frame-based graphical site, and, by addressing these and other design errors, creates a completely accessible site that actually looks slightly better than the original.

The session will go through the demo site reconstruction, showing first how the inaccessible site renders in Lynx, a text-based browser, then showing how to use the Guidelines to identify barriers and make simple corrections, and then showing the accessibility of the final result.

Promotion Efforts and Policy Developments

The development of the Guidelines within the industry setting of the World Wide Web Consortium has already given them good visibility among industry organizations that can become key adopters of the guidelines. The initial release of the Guidelines in May 1999 resulted in a number of commitments by industry organizations to implement the guidelines.

Since then, an increase in the numbers and kinds of policies which require Web accessibility in certain settings have increased the potential for broader adoption of the guidelines. Many of these policy developments are outlined in the WAI reference page on Web accessibility-related policies. These guidelines are a specification developed by the W3C, an international, vendor-neutral industry consortium, and have been developed under W3C process. W3C is not a legislative body ,and the Web Content Accessibility Guidelines specification is not a regulation. However, the guidelines may be informally or formally adopted by different kinds of organizations to clarify what level of accessibility that organization requires for particular Web sites. The fact that policy developments can play such a key role in promotion of the guidelines creates pressure on the development time needed to bring consensus among the many oganizations involved in developing the guidelines as many organizations want the final guidelines available as soon as possible for conformance purposes.

At the same time, the extremely rapid adoption curve of the Web means that there is an ever-increasing group of people to inform about Web accessibility, and that attaining a high degree of accessibility across the Web will be difficult unless the authoring tools themselves make accessible content creation the default mode. In addition, promotion strategies need to reach large numbers of people with at least basic awareness messages. Some of this broad awareness can be pursued with simple resources such as the WAI Quick Tips, and other awareness must be achieved by more in-depth business case data.

Future Areas for Web Content Guidelines Development

Additional work on Web content guidelines development may include additional work to broaden the cross-disability coverage of the Guidelines. Currently the guidelines address functional requirements of visual, hearing, motor and cognitive/neurological disabilities; however the Web Content Guidelines Working Group is currently exploring the possible ways to extend their coverage of cognitive disabilities.

The Guidelines must be periodically updated to address changes in capabilities of user agents including mainstream graphical user interface browsers. In some cases the priority of checkpoints in the Guidelines may be downgraded once browsers or assistive technologies have "caught up to" certain barriers that can exist in Web content. For instance, during the Spring of 199, a number of screen readers became "markup aware" and able to unwrap table markup, which had previously prevented a severe accessibility problem on Web sites. As a result, the priorities for use of table markup shifted before the Guidelines were finalized, although it is still important to mark up tables carefully for optimal reading by screen readers.

Other interim issues which may need addressing include inconsistent implementations of core Web technologies in browsers and authoring tools and how that affects the use of certain checkpoints in the Guidelines. For example, CSS2 (Cascading Style Sheet Level 2) is unevenly implemented in major browsers, and so use of CSS in Web sites must be carefully tested to ensure that the intended appearance results.

As more and more of Web content is developed with XML, this area will also require guidelines development. At the time of writing this paper, the Web Accessibility Initiative is drafting initial versions of XML accessibility guidelines.


The WAI home page, at http://www.w3.org/WAI, has up-to-date information on all the resources of the Web Accessibility Initiative. There are resource and reference areas which are updated frequently; lists of upcoming events; links to WAI's many working groups and interest groups; and an overall interest group for general discussion of Web accessibility issues. There are a great many organizations doing excellent work in the area of Web accessibility, and many of these participate in WAI. WAI's reference links provide a start to finding many of these organizations.

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