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Web Accessibility

Web Accessibility. Achieving Web Accessibility and Usability. Jeffrey P. Bigham CSC 210, March 23, 2011. What is web accessibility?. the degree to which a web page or application is usable by people with different (and changing) abilities visually-impaired people using screen readers

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Web Accessibility

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  1. Web Accessibility Achieving Web Accessibility and Usability Jeffrey P. Bigham CSC 210, March 23, 2011

  2. What is web accessibility? • the degree to which a web page or application is usable by people with different (and changing) abilities • visually-impaired people using screen readers • hearing-impaired people browsing w/out sound • physically impaired people (no mouse!) • color-blind people • cognitively-impaired people (simple language)

  3. Scale of Access • 37 Million Blind People in the World (125 million with low vision) • Increasing • Ageing Population • Situational Impairments • Access technology benefits 25% of web users1 [1] “The Market for Accessible Technology. “ Forrester Research, 2003.

  4. Web Potential for Blind People • Web Advantages • Convertible to Accessible Form • Shop From Home • Blind People Read 7x as Many Books • The Law • U.S. Government Requires Accessibility1,2 • NFB vs. Target Corporation2 [1] Section 508 of the U.S. Rehabilitation Act. [2] Americans with Disabilities Act.

  5. Provide Alt Text <imgsrc=“image.png” alt=“Jeff Balancing 12 umbrellas on his head” />

  6. Tables Confusing when used for layout <th> - table heading element Takes the place of a <td> element. Use <caption> tag to describe table.

  7. Forms, Labels and Color • <label for=“form_element_id”> First Name </label> <input type=“text” name=“firstname” id=“form_element_id”>

  8. No Frames • <frame> is no longer valid HTML • confusing • esp when clicking on content in one frame causes an update in another • <iframe> is ok, but should be avoided too

  9. Javascript • barriers to navigation using keyboard • mousedown instead of click • <div tabindex=0 … > • hidden content • content not functional or visible to AT • off-screen models, inaccessible APIs • lack of user control over content changes • selection boxes, auto-tabs • confusing • altering or disabling normal functionality

  10. Dynamic Content • Two main problems with DHTML/AJAX • need to identify roles/states of scripted widgets • need to convey dynamically changing information • http://www.paciellogroup.com/blog/misc/ARIA/tristatecheck.html

  11. Flash! • Like HTML/Javascript/CSS • Flash can be made accessible • Heavily dependent on user setup • right browser, OS, and AT combination • Avoid if possible!

  12. Audio/Video http://www.youtube.com/watch?v=QRS8MkLhQmM Make your audio/video content accessible provide text alternatives

  13. Usability • Accessibility is more than making access possible, it’s about making content usable for as many people as possible

  14. Keyboard Shortcuts h X X h X X h b b e START

  15. Keyboard Shortcuts .heading { font-weight: bold; } <span class=“heading”> X X <span class=“heading”> X X <span class=“heading”> b b e START

  16. Video! • http://www.youtube.com/watch?v=Nkqhcb1foPI

  17. What is web accessibility? • the degree to which a web page or application is usable by people with different (and changing) abilities • visually-impaired people using screen readers • hearing-impaired people browsing w/out sound • physically impaired people (no mouse!) • color-blind people • cognitively-impaired people (simple language)

  18. Accessibility Resources • http://www.w3.org/WAI/ • http://webaim.org/ • http://www.section508.gov/

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