Self-Describing Data




As mentioned before, the most powerful feature of XML is that it doesn’t define any tags. Creating your
own tags is what makes XML extensible; however, defining meaningful tags is up to you. When creating
tags, it isn’t necessary to abbreviate or shorten your tag names. It doesn’t make processing them any
faster. but it can make your XML documents more confusing or easier to understand. Remember, devel-
opers are going to be writing code against your XML documents. On the one hand, you could certainly
define tags like the following:

<H1>XSLT Programmers Reference
<p><b>Michael Kay</b></p>
</H1>

Using these HTML-based tags might make it easy to be displayed in a browser, but they don’t add any
information to the document. Remember, XML is focused on content, not presentation. Creating the
following XML would be far more meaningful:

<book
<book>

<title>XSLT Programmers Reference</title>
<author>Michael Kay</author>
</book>
</books>