Essential Components of Web Accessibility

Shawn Lawton Henry, W3C WAI

9 May 2005

World Wide Web Consortium (W3C)

• International, vendor-neutral consortium
• Promotes evolution, interoperability, universality
  • Develops core Web standards: HTML, XML, etc.
• Internationally hosted
  • Keio University in Japan
  • MIT in North America
  • ERCIM in Europe
• 14 outreach offices around the world
• Only industry consortium with consensus-based multi-stakeholder accessibility effort

Web Accessibility Initiative (WAI)

• International forum
• Multi-stakeholder
  • Industry
  • Disability organizations
  • Accessibility researchers
  • Government
  • Education
• Consensus-based solutions
• Collaborative W3C working groups
• Opportunities for public comment
• Cross-disability requirements: Visual, auditory, physical, speech, cognitive, neurological

WAI Activities

1. Accessibility in W3C technologies
2. Accessibility Guidelines
3. Evaluation
4. Education and outreach
5. Advanced research and development

Essential Components Interdependent

• Myth: Web accessibility is mainly the responsibility of the Web content producer
• Web accessibility depends on several components working together
• Improvements in components could substantially improve Web accessibility
• WAI guidelines address these components

How the Components Relate - Content

Web content - the information in a Web page or Web application, including:

• natural information such as text, images, and sounds
• code or markup that defines structure, presentation, etc.

How the Components Relate - Content Developer Side

Web developers usually use authoring tools and evaluation tools to create Web content.

• developers - content producers, designers, coders, authors, etc., including developers with disabilities and users who contribute content
• authoring tools - software that creates Web sites
• evaluation tools - Web accessibility evaluation tools, HTML validators, CSS validators, etc.

How the Components Relate - Users Side

People ("users") use Web browsers, media players, assistive technologies, or other "user agents" to get and interact with the content.

• Web browsers, media players, and other "user agents"
• assistive technology, in some cases - screen readers, alternative keyboards, switches, scanning software, etc.
• users' knowledge, experiences, and in some cases, adaptive strategies using the Web

Interdependencies Between Components, Example

Interdependencies Between Components, Example

• Significant interdependencies between the components
• Example, for alternative text on images
  • Technical specifications address alternative text
    • For example, HTML defines alternative text attribute (alt) of image element (img))
    • WAI guidelines define how to implement alternative text for accessibility
  • Developers provide appropriate alternative text wording
  • Authoring tools enable, facilitate, and promote providing alternative text in Web content
  • Evaluation tools help check alternative text exists in content
  • User agents provide human and machine interface to alternative text
  • Assistive technologies provide human interface to alternative text in various modalities
  • Users know how to get the alternative text from user agent and/or assistive technology

When One Component is Weak

Sometimes other components can compensate through "work-arounds"

• require much more effort
• not good for accessibility overall
• often not implemented, result poor accessibility
• sometimes no way to work around, result is impossible for some people with disabilities to use Web site, page, or feature

Weak Authoring Tool Accessibility Support

• developers do more work
  • for example, coding markup directly
• less accessible Web sites
• people with disabilities cannot contribute content

Weak Browsers, Media Players, Assistive Technology, or Content Accessibility Support

• users can do more work
  • for example, using different browsers or assistive technologies to overcome different accessibility issues
• or not accessible at all

Accessibility Feature Implementation Cycle

• If not in one component, other components less likely to implement it
  • Example: developers not implement feature if authoring tools do not support and browsers or assistive technologies do not implement consistently
• When one implements, others more likely to implement:
  • When Web browsers, media players, assistive technologies, and other user agents support accessibility feature, users demand it and developers implement it
  • When developers want accessibility feature, they demand authoring tool make it easy
  • When authoring tools make it easy, developers implement it
  • When in most content, developers and users demand that user agents support it

Guidelines for Different Components

Guidelines for Different Components

Developed by World Wide Web Consortium (W3C) Web Accessibility Initiative (WAI):

• Authoring Tool Accessibility Guidelines (ATAG) addresses authoring tools
• Web Content Accessibility Guidelines (WCAG) addresses Web content, used by developers, authoring tools, accessibility evaluation tools
• User Agent Accessibility Guidelines (UAAG) addresses Web browsers and media players, including some aspects of assistive technologies
• Based on the fundamental technical specifications Web, in coordination with W3C technical specifications (HTML, XML, CSS, SVG, SMIL, etc.)

International Standards Harmonization

Next: WCAG 2.0

Questions?