Use this method to create a document and specify its base
URI (see Section 2.5, “Base URI”). is a IDOMImplementation object:
I.createRootNode(baseURI)
where the argument is optional. If provided,
this value will be available as the baseURI.baseURI attribute of the return Document node.
This method does not create a root element in the
document tree. To create a root element, see Section 12.1, “Document.createElementNS()”; to link the created
element to the document, see Section 5.1, “Node.appendChild()”.
For more information on creating documents, see Section 12, “Creating a document from scratch: factory methods”.