Design Principle
Provide alternative methods to convey information about non-textual objects (images, audio, video, interactive media, applets etc.).
§ Section 508 1944.22 (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).
Rich media covers a broad range of digital objects that enriches a user's audio/ visual experience. It can be interactive, exhibit motion, can be changed programmatically or in direct response to user interaction.
Rich media objects are either embedded in a web page or are rendered by plug-ins or other media handlers. Flash, Java Applets, multimedia and other interactive objects are types of rich media. Examples include:
- Streaming audio, video or movie played in Media player
- Streaming audio broadcast/ podcast
- RSS and/ or news feeds
- Stock market ticker
- Animated Flash presentations embedded in a web page.
- Interactive Flash movie
- Interactive Java applet
Rich media elements, when used appropriately, can supplement and enhance understanding especially for people with cognitive processing, learning and language deficits. However, these elements also present accessibility challenges for people with physical and sensory limitations. Besides inaccessibility to audio/video content, these objects are not designed for access using the keyboard.
To be accessible web developers must::
- Provide text equivalents for all visual and audio content
- Ensure that text-equivalents of dynamic content are updated when the object is changed
- Make the object directly accessible, if an object requires user interaction.
- Provide a mechanism for freezing (stop/pause) the motion if an object creates motion.
- When needed, provide equivalent information in a duplicate alternative format or within an alternative accessible page.
On the web page the <object> element is used to specify the location of the data source the media type associated with the object, other properties/parameters and text descriptor for the object.
Code- text equivalent within <object> element
<object src="http://www.mysite.com/foo.mp3" srctype="audio/mpeg">
<p>alternate text </p>
</object>
<object codetype =" application/java " classid =" java:numSlider.class " width =" 130 " height =" 200 " >
<p> A Java number slider puzzle... .... </p>
< /object>
Code nesting an alternative image for the object with an alt attribute together with the text descriptor
< object classid="java:Press.class" width="500" height="500">
<object data="Pressure.gif" type="image/gif" alt="Description of pressure" >
</object>
<p> As temperature increases, the molecules in the balloon... </p>
</object>
Code with image source nested within <object> element
<object> data=shocknew.dcr
type="application/director" width=288 height=200>
<img src=shocknew.gif alt="Best with Shockwave">
</object>
