W3C Web Accessibility Initiative


This page contains material related to a presentation at the Web Accessibility Best Practices Evaluation Training in Sankt Augustin, Germany on 25 October, 2005, as part of the WAI-TIES Project (WAI - Training, Implementation, Education, Support). It is not intended to stand-alone; rather, it is primarily provided as reference material for participants in the training.

Scope of Training and Materials: This one-day training focused on select topics that were particularly suited to the circumstances of this specific training session. It did not to cover all aspects of evaluating Web accessibility, and did not cover all Web Content Accessibility Guidelines (WCAG) 1.0 checkpoints.
No Endorsement or Recommendation of Evaluation Tools: W3C/WAI does not endorse Web accessibility evaluation tools and does not recommend one tool over another. Some tools were listed, demonstrated, and used in activities in this training. Mention of a specific tool does not imply endorsement nor recommendation. WAI does provide a comprehensive list of Evaluation, Repair, and Transformation Tools for Web Content Accessibility.


Web Accessibility Perspective

Shadi Abou-Zahra, W3C / WAI

Last updated: 1 November 2005

What is Web accessibility?

Why is it an issue?

Examples of barriers

Who is affected?

People with:
  • Visual, hearing, physical, cognitive, or neurological disabilities
  • Aging related deficiencies
  • Temporary or situational limitations
  • Social or economical limitations

Are there more benefits?

What is Web Content?

different compents of a Web page such as pictures, text, diagrams, structures, etc.

Any information in a Web page or Web application, including:

Developer perspective

Web developer with a symbolic path to represent information that passes through authoring tools and evaluation tools in order to be published Web content.

User perspective

Web user with a symbolic path to represent Web content that passes through user agents and assistive technologies in order to be acquired or experienced information.

Authoring and rendering

specific example for alternative text on images which is a requirements by the Web Content Accessibility Guidelines 1.0. Web developers provide text alternatives for the images using authoring tools. The HTML specification provides a mechanism to supplement images with such text. Finally, this redundant coding is used by browsers and assistive technology to convey the information to the end users according to their preferences, for example visually, through voice synthesis, or in form of text.

When components are weak...

Symbolic paths around authoring tools or through multiple browsers and assistive technologies represent how Web developers and users need to spend more effort working around weak components that do not support accessibility.

Sometimes other components can compensate through "work-arounds"

Components of Web accessibility

illustration with labeled graphics of computers and people. at the top center is a graphic with numbers, a book, a clock, and paper, labeled 'content'. coming up from the bottom left, an arrow connects 'developers' through 'authoring tools' and 'evaluation tools' to 'content' at the top. coming up from the bottom right, an arrow connects 'users' to 'browsers, media players' and 'assistive technologies' to 'content' at the top. below these are 'accessibility guidelines' which include 'ATAG' with an arrow pointing to 'authoring tools' and 'evaluation tools', 'WCAG' pointing to 'content', and 'UAAG' pointing to 'browsers, media players' and 'assistive technologies'. at the very bottom, 'technical specifications (HTML, XML, CSS, SVG, SMIL, etc.)' forms a base with an arrow pointing up to the accessibility guidelines.

Web Content Accessibility Guidelines (WCAG)

Web Content Accessibility Guidelines 1.0

WCAG 1.0 Structure Diagram

diagram showing relationship between all WCAG 1.0 Documents, detailed description at www.w3.org/WAI/intro/wcag20-desc.html#1all

Example of WCAG 1.0 Guideline

excerpt of guideline and checkpoint text at http://www.w3.org/TR/WCAG10/#gl-color

WCAG 1.0 Techniques Gateway

excerpt from http://www.w3.org/TR/WAI-WEBCONTENT-TECHS/#tech-color-convey

Example of WCAG 1.0 Technique

excerpt from http://www.w3.org/TR/WCAG10-CSS-TECHS/#style-info-not-in-color-alone

Components of Web accessibility

illustration with labeled graphics of computers and people. at the top center is a graphic with numbers, a book, a clock, and paper, labeled 'content'. coming up from the bottom left, an arrow connects 'developers' through 'authoring tools' and 'evaluation tools' to 'content' at the top. coming up from the bottom right, an arrow connects 'users' to 'browsers, media players' and 'assistive technologies' to 'content' at the top. below these are 'accessibility guidelines' which include 'ATAG' with an arrow pointing to 'authoring tools' and 'evaluation tools', 'WCAG' pointing to 'content', and 'UAAG' pointing to 'browsers, media players' and 'assistive technologies'. at the very bottom, 'technical specifications (HTML, XML, CSS, SVG, SMIL, etc.)' forms a base with an arrow pointing up to the accessibility guidelines.

Putting it all together

illustration with arrow going from content at top through authoring tools at left to content at the bottom, and an arrow going from the content at the bottom through assistive technologies and user agents at the right and back to content at the top