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Enhancing Web Accessibility with JavaScript: Techniques for Universal Design

Discover essential strategies for building accessible JavaScript applications with a focus on universal design. This comprehensive guide discusses the importance of semantic HTML as the foundation for accessibility, as well as the role of progressive enhancement in ensuring that all content is usable without JavaScript. Explore techniques like ARIA (Accessible Rich Internet Applications) for improving communication with assistive technologies, alongside keyboard navigation and user control. Make accessibility an integral part of your web development practice, benefiting all users.

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Enhancing Web Accessibility with JavaScript: Techniques for Universal Design

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  1. Accessible JavaScript Techniques Patrick Fox – Razorfish Becky Gibson - IBM

  2. Building Accessibility(A11y) • Universal design • Design for all, everyone benefits • Accessibility is so commonplace, you don’t notice • Curb cuts, access ramps • Closed captioning • Goal: accessibility becomes ubiquitous

  3. JS A11y Starts with the Basics: • Old school accessibility: • Semantic markup • Equivalent alternatives • Images • Skip navigation • Natural tab order

  4. Semantic HTML is the Foundation • Conveying meaning of markup to assistive technology • Bad: <span class="title">Page Title</span> • Good: <h1>Page Title</h1> • Key component of SEO

  5. Accessible JavaScript • But wait…

  6. Progressive Enhancement • An essential part of making JS accessible is not to rely on it at all • All page content should be accessible without JS • Role of JS is purely to enhance a fully functioning and accessible site

  7. Progressive Enhancement Example: my.SXSW.com/events • Problem: • Does not work w/o JS • Content remains hidden w/o JS

  8. Progressive Enhancement Example: SXSW.com Panel • Under the hood: • Solutions: • Establish basic page flow • Change DIV’s to meaningful elements • Add JS events unobtrusively • $('.eventName').click(function () {…});

  9. Progressive Enhancement:JS vs. Non JS CSS • Control the display of your widgets or hidden content using a simple script: • <body class="js-disabled"><script type="text/javascript">document.body.className =document.body.className.replace('js-disabled', 'js-enabled');</script> • CSS: .js-enabled .hidden {display:none;}

  10. Progressive Enhancement: Summary • Start with a fully accessible site that works without JS • Control display of hidden content with JS script • Use unobtrusive JS techniques to keep layers separate and code maintainable

  11. Accessible JS • Key Points • Device independent navigation • Provide means to navigate a page and widgets using keyboard and mouse. • Access to pertinent page content • Hidden content(e.g. tooltips, hidden lists, menus, tabs) should be available to all users • User control or awareness • Give the user means to control their experience • Provide mechanisms for alerting the user to pertinent changes in the page. • Default browser behavior • Altering or disabling the normal functionality of the browser can confuse or disorient the user.

  12. Keyboard Support Example • Goal: mimic default browser behavior • Keyboard navigation • Up/down arrows • Widget keyboard navigation recommendations:http://dev.aol.com/node/757 • Focus Management • Roaming tabindex

  13. Keyboard Support Example • Keydown event listener code:

  14. But that only gets you so far… • There’s a gap… • There’s no way to communicate common Web 2.0 events, concepts, states to AT

  15. Communication Breakdown • HTML is limited • not intended for creation of applications, complex widgets • No built-in way to convey: • Widget roles • DOM updates(Ajax, display changes)

  16. Bridging the Gap: WAI-ARIA • Addresses Web 2.0 Accessibility Issues • Backwards compatible, forward thinking • Developed at IBM, donated to W3C • At last call draft status • Support: • Firefox, IE 8 • Initial implementation in Opera 9.5, Safari 4 • Window-Eyes, JAWS and NVDA screen readers • Used by IBM, Dojo, AOL, Yahoo, Google, SAP…

  17. ARIA Details • Roles • States and Properties • Keyboard Support • Landmarks • Live Regions

  18. ARIA - Roles • Add semantics to scripted user interface (UI) elements A passport or caller Id for your controls!

  19. ARIA States & Properties • Additional Details about the control • Label, multi-selectable, readonly, required, etc. • States that may change over time • Expanded/collapsed, checked, hidden, etc.

  20. ARIA Example – Tree Structure Role = tree(on outer container) Role = treeitemaria-expanded=true(on open Africa node) Role = treeitemaria-selected=true(on highlighted Egypt child node with no children) Role = treeitemaria-expanded=false (on closed Australia node)

  21. ARIA – Keyboard Support • Make items focusable via tabindex attribute • Add keyboard event handling • Mimic the behavior of desktop controls • Minimize tab key navigation

  22. ARIA – Live Regions • Identify and announce updated regions to support Ajax Announce new and important information and additions

  23. ARIA Live Regions • Perceivable sections are identified with region role • Live indicates region is updated • Values of: Off, Polite, Assertive • Atomic identifies the extent of updates • True – entire region is updated and relevant • False – only changed element needs to be presented to user • Controls identifies the element which triggers an update • Supported beginning in Firefox 3 and JAWS 10

  24. ARIA Example - Live Regions • Editing auto save notification • live=polite; atomic=true; • Server maintenance notification • Live=assertive; atomic=true; • New mail - speak new entries • Live=polite; atomic=false; <div role=“region” aria-live=“assertive” aria-atomic=“true”> Wile E. Coyote’s Gravity Lessons </div>

  25. Live Region Demo <div id="main" role="main"> <div id="content" role="document" aria-live="assertive"> Select a panel name to load the description. </div> </div>

  26. ARIA - Landmarks • Identify important regions on the page

  27. ARIA Landmark Roles • Makes finding and navigating to sections of the page easier • Application • Banner • Complementary • Contentinfo • Main • Navigation • Search • Header Example: <div role=”navigation">

  28. banner Navigation ARIA Landmarks - Example Main

  29. All of this sounds like a lot of work... • ...and it is more work, but not a lot. • Use a JavaScript Toolkit! • Dojo • JQuery • YUI • GWT • They make progressive enhancement, unobtrusive JS and accessible JS EASY(ER) to implement

  30. Dojo Mail Demo

  31. Summary • Accessible JavaScript is made possible by creating layers of accessibility • Old-school accessibility • Progressive enhancement • Bridge the gap with WAI-ARIA • Follow JS widget standards and recommendations • WAI-ARIA best practice recommendations • DHTML Style Guide WG recommendations

  32. Thank you! • Becky Gibson, IBM – gibsonb@us.ibm.com • Patrick Fox, Razorfish – patrick.fox@razorfish.com • Slides available at: Knowbility’s KnowWiki • http://wiki.knowbility.org/sxswi-2010/

  33. Becky’s Resources • Becky’s Accessibility Presentations and Papers • http://www.weba11y.com/Presentations/presentations.html • ARIA Roadmap, Best Practices, Primer, Specifications • http://www.w3.org/WAI/intro/aria • Mailing list for ARIA issues • http://lists.w3.org/Archives/Public/wai-xtech/ • Free-ARIA Google Group http://groups.google.com/group/free-aria • Dojo • Home - http://www.dojotoolkit.org/ • Reference Guide – http://www.dojotoolkit.org/reference-guide/ • Accessibility Sections in Dijit Reference Section of book • http://www.dojotoolkit.org/reference-guide/dijit/index.html • A11y info included on each dijit page

  34. Patrick’s Resources • DHTML style guide working group(DSGWG) nav recommendations • http://dev.aol.com/node/757 • WCAG2 Overview • http://www.w3.org/TR/WCAG20/#keyboard-operation • WAI-ARIA Authoring Practices 1.0 • http://www.w3.org/TR/wai-aria-practices/ • Introduction to WAI ARIA • http://dev.opera.com/articles/view/introduction-to-wai-aria/ • Improving Accessibility Through Focus Management • http://www.yuiblog.com/blog/2009/02/23/managing-focus/

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