XML and the future - Page 7

Lisa Seeman

September 8, 2000

XML is a structured mark up language. It will allow for as many different tags as you want. It allows you to present the same information in as many different ways as you want. It allows you to do all the things we have been talking about, with ease.

What most of this article has been trying to do is separate content from presentation. In other words, to put your styles into a style sheet, and have your main document full of valid marked up content. That is exactly what happens with XML.

As your work switches to XML it is the perfect time to create a disability friendly protocol.

You can create reusable DTDs and schemas, with semantically-rich languages, element types that allow classification and grouping, element types that identify important text content. Point at XHTML modules for OBJECT, MAP element, SMIL switch etc. You can also provide accessible documentation and start your company off on the right XML foot.

When making your own DTD be sure to include a required description attribute in each element. Even better, make a rich description required for visual and auditory elements. Also include as many alternative values as possible, similar to aural attributes in CSS.

You can sometimes make a short cut by creating attributes with default values. Care should be taken that the default is always applicable, the #FIXED keyword states that the attribute must always have the default value. So, for example, giving a bullet the fixed description "new point", may be helpful, but a picture element should not have a default description of "our logo", if that is not always the case.

You can further aid navigation by using extended links to show the relationship between resources.

<ELINK XML-LINK="EXTENDED" ROLE="ANNOTATION">

<LOCATOR XML-LINK="LOCATOR" HREF="text.loc">The Text
</LOCATOR>

<LOCATOR XML-LINK="LOCATOR" HREF="ann.loc">Annotations
</LOCATOR>

<LOCATOR XML-LINK="LOCATOR" HREF="litcrit.loc">Literary Criticism

<ELINK>

We do not yet know how special devices will work with all of the XML attributes, and what problems may occur. For example, xml:space may prove problematic for some readers.

The ACTUATE attribute from XML linking specification (XLL), determines how the link is traversed. Automatically activated links may disorient disabled users. The same is true for using pop up windows with the SHOW attribute.

XHTML

"alt" is a required attribute of the img element. But you can also use the "longdesc" attribute when more text is needed to explain the image.

While XHTML 1.0 provides an "alt" attribute for the applet element, you can use the applet element as a containing tag to include rich equivalents for applets.

The following example by Wendy Chisholm illustrates how one might provide an equivalent alternative for an applet that generates a "roll-over" graphic, which lists the site's sponsors:

<applet codebase="URI" width="%Legnth" height="%Legnth" ...> 

	<dl> <dt>A list of our sponsors:</dt> 
	<dd>Acme Novelty Corporation of America
	<dd>Acme Africa</dd> 
	<dd>Acme Europa</dd> 
	</dl> 
</applet>

Use the XHTML modules for the object and map elements.

Most of the advice for HTML holds true for XHTML. You want to use mark up and do so properly, only with XHTML you have to do this anyway. For frames you should still put equivalent information within the noframes. For iframes provide inline alternative content. You can now use the "longdesc" attribute to provide equivalent access to the content of each frame.

As new technologies move forward, new problems for the disabled will follow in their wake. So keep up to date with the latest Web Accessibility Initiative guidelines, and check up on the developments with their accessibility initiative.

I am making an XSS ( XML equivalent of CSS) for anyone who wants it. I will post it here when it is done. So get ready for XML, but bear in mind that not all disabled readers will be using the latest technology. It may take a while until the braille and speech readers will be XML compatible, and then not everyone will be replacing their equipment. So keep those old HTML sites accessible.

And write to me with any problems.

Best of luck