In the previous chapter, we discovered ways in which multimedia content can be rendered most accessibly. This chapter explores in greater detail the tools that create and render that content. Scripts, applets, and plug-ins are some of the most powerful tools available to Web authors who wish to add a high level of interactivity and variety to the content they offer on their Web pages. Use of sophisticated interactive tools can greatly increase the functionality of Web pages but too often results in content that is inaccessible. It need not be so. As the need for universal access has become more widely understood and accepted, cooperative efforts have emerged for the purpose of creating cross-browser accessibility solutions and alternatives for the use of plug-ins, applets, and scripts. IBM, Sun Microsystems, and the National Center for Accessible Media are among the leaders whose work in publicizing and implementing W3C recommendations and Section 508 federal standards for accessible emerging technologies we explore in this chapter.
To ensure that Web pages that employ scripts, applets, and plugins can deliver content that is accessible to everyone, Web authors must be aware of accessibility principles and fully integrate those principles into programming and development. This chapter applies general accessibility principles to the process of interactive Web page development, regardless of the script, applet, or plug-in chosen for the task. We ask you once again to think always in terms of delivering content that is separate from presentation (see Chapter 15 for further discussion of this point). Important information exchange can thus be made accessible for all users, not just those with graphical browsers attached to fast networks.
HTML Elements and Attributes Addressed in This Chapter
<script>, <object>, <noscript>, <noframes>, <applet>
type, src, language, defer
Accessibility Checkpoints and Standards Addressed in This Chapter
Web Content Accessibility Guidelines 1.0 Checkpoints
6. Ensure that pages featuring new technologies transform gracefully.
6.3. Ensure that pages are usable when scripts, applets, or other programmatic objects are turned off or not supported. If this is not possible, provide equivalent information on an alternative accessible page. [Priority 1]
6.4. For scripts and applets, ensure that event handlers are input device-independent. [Priority 2]
8.1. Make programmatic elements such as scripts and applets directly accessible or compatible with assistive technologies. [Priority 1 if functionality is important and not presented elsewhere, otherwise Priority 2]
9.3. For scripts, specify logical event handlers rather than device-dependent event handlers. [Priority 2]
12.1. Title each frame to facilitate frame identification and navigation. [Priority 1]
Section 508 Standards, §1194.22
(i) Frames shall be titled with text that facilitates frame identification and navigation.
(l) When pages utilize scripting languages to display content, or to create interface elements, the information provided by the script shall be identified with functional text that can be read by assistive technology.
(m) When a Web page requires that an applet, plug-in or other application be present on the client system to interpret page content, the page must provide a link to a plug-in or applet that complies with §1194.21 (a) through (l).