javascript document implementation

Returns a reference to the W3C DOMImplementation object, which represents, to a limited degree, the environment that makes up the document containerthe browser, for our purposes. Methods of the object let you see which DOM modules the browser reports supporting. This object is also a gateway to creating virtual W3C Document and DocumentType objects outside of the current document tree. Thus, in Netscape 6 you can use the document.implementation property as a start to generating a nonrendered document for external XML documents. See the DOMImplementation object for details about the methods and their browser support.