document.implementation.createDocument with current document's DOCTYPE. On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". PASS doc = document.implementation.createDocument(null, null, document.doctype) did not throw exception. PASS doc.doctype is doctype PASS doc.firstChild is doctype PASS document.doctype is null PASS successfullyParsed is true TEST COMPLETE PASS successfullyParsed is true TEST COMPLETE