Extensible Markup Language, XML, was derived from SGML (ISO 8879), and provides exchange of a wide variety of data over the Web, and elsewhere. As the simple MS IE Javascript nearby sample shows, the HTML page contents can be controlled by the nodes in a note.xml file.
A recent search of Yahoo, using just 'XML', yielded some 35 million hits. It is important an open, versatile, consistent method can be found to exchange data between diverse systems. At the present time, 2004, it appears, XML, has fill this place, at least for now ... ;-))
Once you understand even a little of this technology, it is easy to adopt it as part of some things you do. You frequently see it used in a simplistic way, in the startTag, Data, endTag context, like, if you want to quote what somebody said, you can use :-
<quote>
She said this
</quote>
Part of the XML syntacs is rigid. For each startTag there must
be an endTag, so you have -
<ATAG>data</ATAG>. Start, data, and end, simple.
If you, as a programmer, build an XML parser, there are some test suites you can
try your code on.
Another example using Microsoft XMLDOM and Javascript is here, using note2.xml ...