e4x.js implements the optional E4X features described in ECMA-357 2nd Edition Annex A.
The jQuery E4X DOM Plugin (jquery.e4x-dom.js) adds support for XML nodes as DOM
nodes in jQuery. It also adds support for converting jQuery objects into XMLLists.
If an XML element does not have a namespace, it is assigned the XHTML 1.x namespace.
To change the default assigned namespace, change jQuery.defaultXMLNamespace
accordingly.