Retrieves an attribute value by local name and namespace URI.
Per [XML Namespaces] , applications must use the value null as the namespaceURI parameter for methods if they wish to have no namespace.

Parameters:

namespaceURI		The namespace URI of the attribute to retrieve.
localName		The local name of the attribute to retrieve.

Returns:  The Attr value as a string, or the empty string if that attribute does not have a specified or default value.

Exceptions:

DOMException

NOT_SUPPORTED_ERR: May be raised if the implementation does not support the feature "XML" and the language exposed through the Document does not support XML Namespaces (such as [HTML 4.01]).

Since:  DOM Level 2