To declare an XML namespace, you use an attribute whose name has the form:
xmlns:prefix
--OR--
xmlns
These attributes are often called xmlns attributes and their value is the name of the XML namespace being declared; this is a URI. The first form of the attribute (xmlns:prefix) declares a prefix to be associated with the XML namespace. The second form (xmlns) declares that the specified namespace is the default XML namespace.
For example, the following declares two XML namespaces, named [URL unfurl="true"]http://www.tu-darmstadt.de/ito/addresses[/URL] and [URL unfurl="true"]http://www.tu-darmstadt.de/ito/servers.[/URL] The first declaration associates the addr prefix with the [URL unfurl="true"]http://www.tu-darmstadt.de/ito/addresses[/URL] namespace and the second declaration states that the [URL unfurl="true"]http://www.tu-darmstadt.de/ito/servers[/URL] namespace is the default XML namespace.
<Department
xmlns:addr="[URL unfurl="true"]http://www.tu-darmstadt.de/ito/addresses"[/URL]
xmlns="[URL unfurl="true"]http://www.tu-darmstadt.de/ito/servers">[/URL]