Support for IE (1)
Tidied up 'Node Type' definitions (2)

(1): Selectors in jQuery appear to currently not operate in the same manner across browsers (IE/FireFox). In Firefox you can ignore the namespace of an element name, whereas in IE you must specify it. To get around this, instead of "find('myTag')" you can instead use "find('[@nodeName=myNS:myTag]')" - which I have done.
(2): Certain non-compliant browsers don't have NodeType definitions. I now explicitly redefine them in this plugin.