Gets the namespace URI of the node.
Standard HTML nodes will always have the default namespace to simplify XPath queries even if an xmlns is explicitely specified in XHTML documents.
For all non-standard HTML 4.01 elements that define an xmlns, NamespaceURI will return the namespace URI.
Standard HTML nodes will always have the default namespace to simplify XPath queries even if an xmlns is explicitely specified in XHTML documents.
For all non-standard HTML 4.01 elements that define an xmlns, NamespaceURI will return the namespace URI.