Definition
DOM Standard defines DOMImplementation
[Exposed=Window]
interface DOMImplementation {
[NewObject] DocumentType createDocumentType(DOMString qualifiedName, DOMString publicId, DOMString systemId);
[NewObject] XMLDocument createDocument(DOMString? namespace, [LegacyNullToEmptyString] DOMString qualifiedName, optional DocumentType? doctype = null);
[NewObject] Document createHTMLDocument(optional DOMString title);
boolean hasFeature(); // useless; always returns true
};