Understanding Universal Web Accessibility

1
Understanding Universal Web Accessibility

• Bebo White
• SLAC
• bebo_at_stanford.edu
• 27 Sept 2002

2
What Does Accessibility Mean?
"The power of the Web is in its
universality. Access by everyone
regardless of disability is an essential
aspect. -- Tim Berners-Lee W3C Director
Inventor of the World Wide Web
3
Who Are the Disabled?

• An estimated 20 of Americans have some form of
  disability (Microsoft Web site)
• Global statistics are probably similar
• Not just the obvious
• Blind, deaf, severe motor disabilities
• But more commonly
• Color deficiency, reading disorders, aging

4
The ADA and Section 508

• In 1998, the U.S. Congress amended the
  Rehabilitation Act to require Federal agencies to
  make their electronic and information technology
  accessible to people with disabilities
• Inaccessible technology interferes with an
  individual's ability to obtain and use
  information quickly and easily
• Disabled employees must have access to
  information comparable to others

5
The ADA and Section 508 (cont)

• Section 508 was enacted
• to eliminate barriers in information technology
• to make available new opportunities for people
  with disabilities
• to encourage development of technologies that
  will help achieve these goals
• Applies to, but is not limited to, computers,
  ancillary equipment, software, telecommunication
  products, information kiosks, Web sites,
  multimedia, and office equipment

6
Web Content Accessibility Guidelines (WCAG)

• Published by the W3C
• Now at Version 1.0
• http//www.w3.org/TR/WAI-WEBCONTENT

7
General WCAG 1.0 Principles

• Provide a text equivalent for every non-text
  element (e.g., via "alt", "longdesc", or in
  element content).
• Ensure that all information conveyed with color
  is also available without color, for example from
  context or markup.
• Clearly identify changes in the natural language
  of a document's text and any text equivalents
  (e.g., captions).

8
General WCAG 1.0 Principles

• Organize documents so they may be read without
  style sheets.
• Ensure that equivalents for dynamic content are
  updated when the dynamic content changes.
• Until user agents allow users to control
  flickering, avoid causing the screen to flicker.
• Use the clearest and simplest language
  appropriate for a site's content.

9
Accessibility Tools

• Bobby - http//bobby.watchfire.com/bobby/html/en/i
  ndex.jsp
• http//www.w3.org/WAI/ER/ existingtools.html

10
Bobby and the HKU Site
11
Universal Accessibility
Anyone or anything using any kind of Web
client technology on any Web-enabled platform
should be able to visit any site and get a
full and complete understanding of the
information contained therein as well as
have the full and complete ability to interact
with that site as necessary
12
Internet
Web Server
13
Benefits of Universal Accessibility

• Increase market share and audience reach
• Improve usability for non-disabled and disabled
  visitors
• Support for low literacy levels
• Improve search engine listings and resource
  discovery
• Support for the Semantic Web
• Repurpose content for multiple formats or devices
• Increase support for internationalization
• Assisting access for low-bandwidth users

14
Benefits of Universal Accessibility (2)

• Improve efficiency
• Reduce site maintenance
• Site search engine improvements
• Repurposing content
• Address server-load
• Address server-bandwidth
• Demonstrate social responsibility
• Reduce legal liability

15
Market Share Benefits of Accessible Web Site
Design
(from Andrew Arch and Chuck LeTourneau)
16
Technical Efficiency Benefits of Accessible Web
Site Design
(from Andrew Arch and Chuck LeTourneau)
17
The Key to Universal Accessibility is Repurposing

• Content is what you say
• Presentation is how you present it
• Content is invariant
• Presentation is variable
• Repurposing is matching content to presentation
• Tools for repurposing are available now

18
Presentation
Content
(e.g., CSS, XSL, XHTML, XML)
Complex System
Interface 1
User 1
(e.g., RDF)
Meta-layer of all communication between user
and system
Interface 2
User 2
Interface 3
User 3
Use Profiles
Interface Generator
19
Accessible design is not only good design, its
good sense!