XML Companion, The, Third Edition

Defaults

When every element has a prefix, the document can become difficult to read, and the extra characters certainly add to its size. Fortunately, the standard includes the concept of a default namespace.

Element defaults

Elements can belong to a default namespace, but this is done by declaring the namespace using an attribute named 'xmlns', with no suffix (as suggested earlier):

<document
						xmlns="file:///DTDs/document.dtd"
          xmlns:X="http://www.w3.org/TR/REC-html40">
  ...<description>...</description>...
  ...<X:td>An HTML table cell.</X:td>...
</document>

Overriding defaults

The default namespace can be changed at any point in the document hierarchy. This is an ideal technique when a sufficiently large XML fragment is embedded:

 <document xmlns="file:///DTDs/document.dtd" ...