Web Development and Design Foundations with XHTML, 5th Edition

11.13 Accessibility and Multimedia/Interactivity^455

favorite sites (http://del.icio.us), Google’s e-mail (http://gmail.google.com), Amazon’s A9

search engine (http://www.a9.com), and Microsoft Live (http://www.live.com).

Ajax Resources

Ajax is a very hot topic on the Web right now and there are many resources and articles

available. Some helpful sites are listed here:

●http://www.ajaxpatterns.org

●http://www.webpasties.com/xmlHttpRequest

●http://www.alistapart.com/articles/gettingstartedwithajax

●http://www.tizag.com/ajaxTutorial

CHECKPOINT 11.3

1. Describe two uses of JavaScript.


2. Describe two uses of DHTML.


3. Describe two uses of Ajax.

11.13 Accessibility and

Multimedia/Interactivity

Multimedia and interactivity can help to create a compelling, engaging experience for

your Web site visitors. Please keep in mind that not every Web visitor will be able to

experience these features.

●Provide links to free downloads for the plug-ins used by your multimedia. (The

code provided to incorporate Flash media and Quicktime media includes these

plug-in links.)

●Text descriptions and equivalent content (such as captions) of audio and video

will provide access to those with hearing challenges.

●When you work with multimedia developers and programmers to create Flash

animations or Java applets for your site, be sure to request features to provide

accessibility—keyboard access, text descriptions, and so on. If you use Flash, a

Java applet, or DHTML for site navigation—be sure it can be accessed with a

keyboard and/or provide plain text navigation links in the footer section of the

pages. Adobe provides a good resource for Web developers at their Accessibility

Resource Center (http://www.adobe.com/resources/accessibility).

●Section 508 requires that certain rates of screen flickering (frequency greater than

2 Hz and lower than 55 Hz) are avoided. WCAG 2.0 guidelines (2.3.1) recommend

that a Web page not contain any item which flashes more than three times per sec-

ond. This is to prevent optically induced seizures. You may need to work with your

multimedia developer to ensure that dynamic effects perform within a safe range.

●If you use JavaScript, be aware that some visitors may have JavaScript disabled

or are unable to manipulate the mouse. Section 508 requires that your site is

WWW

Focus on Accessibility