HTML and CSS Reference
15.8. Using XML
Our address example is trivial. It hardly scratches the surface of the wide
range of applications that XML is suited for. To whet your appetite, here
are some common uses for XML that you will certainly be seeing now and
in the future.
15.8.1. Creating Your Own Markup Language
We touched on this earlier when we mentioned that the latest versions
of HTML are being reformulated as compliant XML DTDs. We cover the
impact XML has on HTML in the next chapter.
But even more significantly, XML enables communities of users to create
languages that best capture their unique data and ideas. Mathematicians,
chemists, musicians, and professionals from hundreds of other disciplines
can create special tags that represent unique concepts in a standardized
way. Even if no browser exists that can accurately render these tags in
a displayable form, the ability to capture and standardize information is
tremendously important for future extraction and interpretation of these
For more mainstream XML applications with established audiences, it is
easy to envision custom browsers being created to appropriately display
the information. Smaller applications or markets may have more of a
challenge creating markup languages that enjoy such wide acceptance.
Creating the custom display tool for a markup language is difficult; deliv-
ering that tool for multiple platforms is expensive. As we've noted, you
can mitigate some of these display concerns through appropriate use of
stylesheets. Luckily, XML's capabilities extend beyond document display.
15.8.2. Document Exchange
Because XML grew out of the tremendous success of HTML, many people
think of XML as yet another document-display tool. In fact, the real