1998 Conference Proceedings

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WEB ACCESSIBILITY: PROGRESS ON THE TECHNICAL FRONT

Daniel Dardailler
Project Manager, Web Accessibility Initiative
World Wide Web Consortium
danield@w3.org 
http://www.w3.org/WAI

Judy Brewer Director, Web Accessibility Initiative International Program Office
World Wide Web Consortium
jbrewer@w3.org 
http://www.w3.org/WAI

Web Accessibility Initiative: Progress on the Technical Front

The World Wide Web Consortium's (W3C's) Web Accessibility Initiative (WAI) has already resulted in improvements to the technology of the Web. This is largely through the efforts of one WAI working group in 1997 and early 1998, which has been focusing on improving the accessibility of all W3C specifications going to "Recommendation" status. This session will look at those improvements, as well as upcoming technical issues and as yet unaddressed requirements.

In addition, the presenters will review related work under the WAI Technical Activity, including development of guidelines for browsers, authoring tools, and page authoring.

Accessibility improvements in HTML 4.0:

HTML 4.0, released as a W3C Recommendation in December, 1997, contains a number of accessibility improvements as a result of collaboration between the W3C HTML Working Group and the W3C's Web Accessibility Initiative (WAI).

Overall, these improvements affect several areas with regard to accessibility. They enhance the structure of documents; they separate content presentation from structure through incorporation of style sheets; they provide new mechanisms for alternative presentation of content; and they include new features to facilitate navigation and orientation. Specific improvements include:

Accessibility improvements in CSS2 (Cascading Style Sheets: Level 2):

Given the importance for Web Accessibility of style-sheet driven design becoming widely adopted, it is tempting to say that anything that facilitates page authoring with CSS constitutes an accessibility improvement.

In that regard, CSS2 is a leap forward in functionality. One of the most important aspect in CSS2 with regard to accessibility is the integration of Aural Cascading Style Sheet (ACSS, pronounced "access") properties in the base language.

For instance, the 'cue' property allows the CSS author to attach specific sounds to the presence of headers:

H1 {cue: url(pop.au) }

ACSS, with more than 20 specific properties, will allow the definition and sharing of advanced voice-based presentations for the Web. This feature should help the development of aural media which is so important for visually impaired users, and likewise for those who cannot read.

CSS2, like HTML 4.0, adds a wide range of new target media (TTY, Braille, embossed, etc.) for categorization of different user environments.

The support of 'grid' media, used both in dynamic Braille and non-graphic terminals (front-end for most screen readers) is crucial for accessibility.

Lastly, the ability to add text to the normal flow of presentation was retained for CSS2, partly due to discussion regarding user accessibility requirements between the WAI technical group and the CSS working group. For instance:

H2:before { content: "Level 2 header, " }

allows users to announce particular kinds of headers to help track the logical structure of a document. Others important new features in CSS2 include:

Additional W3C specifications under review by the Web Accessibility Initiative:

SMIL (Synchronized Multimedia Interchange Language) offers a neutral means to exchange multimedia content across the breadth of the Web. At the time of this writing, the group is still reviewing the specification.

XML (eXtensible Markup Language) has reserved a namespace for accessibility concerns. The WAI technical group will need to explore how to convey accessibility semantics, easily expressed in a single DTD (Document Type Definition) such as HTML, in a meta-language like XML which can be used to derive any kind of DTD.

RDF (Resource Description Framework) introduces knowledge about resources to the Web, and is also being tracked for its potential in providing accessibility support (such as attaching descriptive and logical reading instructions to a TABLE in a document).

WAI Accessibility Guidelines:

On February 3, 1998, the W3C's Web Accessibility Initiative released a working draft of "WAI Accessibility Guidelines: Page Authoring." These guidelines include a checklist for page accessibility and more detailed explanations of accessible page design principles.

The "WAI Accessibility Guidelines: Page Authoring" are based on unified guidelines compiled by the Trace Research and Development Center from dozens of Web accessibility guidelines around the world. The WAI page authoring guidelines also incorporate the accessibility improvements from HTML 4.0 and expected accessibility improvements in CSS2. Developing these guidelines in close coordination with W3C specifications ensures that best-practice guidance does not fall behind the state of the technology.

In the page author guidelines, measures to increase accessibility are grouped into the following categories: structure, navigation, and alternative format. Each item in the guidelines is designated as either "required" meaning that one or more groups of users cannot understand a page if that guideline is not followed; or "recommended" if it will make it easier for one or more groups to understand and use.

The checklist at the end of the page author guidelines provides an initial means to evaluate the accessibility of Web pages; in addition, the page author guidelines include recommendations for a number of different testing approaches.

In addition, WAI working groups are developing accessible browser guidelines and accessibility authoring tool guidelines in coordination with manufacturers, user groups, and others involved in the Web Accessibility Initiative.

References:

Web Accessibility Initiative home page: http://www.w3.org/WAI 

The HTML 4.0 Specification is available at http://www.w3.org/TR/REC-html40 

Cascading Style Sheets (CSS), level 1 is a W3C Recommendation available at http://www.w3.org/TR/REC-CSS1 

A Working Draft of CSS, level 2 is available for public comment at http://www.w3.org/TR/WD-CSS2 

A Working Draft of "WAI Accessibility Guidelines: Page Authoring" is available at http://www.w3.org/TR/1998/WD-WAI-PAGEAUTH-0203 


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