Jacek Caban (@jacek) commented about dlls/mshtml/tests/es5.js:
var doc = iframe.contentWindow.document; ok(!(doc instanceof Object), "doc is an instance of Object"); ok(!(doc.implementation instanceof Object), "doc.implementation is an instance of Object");
ok(!(doc.implementation instanceof DOMImplementation), "doc.implementation is an instance of DOMImplementation");
ok(doc.implementation instanceof iframe.contentWindow.DOMImplementation, "doc.implementation is not an instance of iframe's DOMImplementation");
It would be nice to add a few more simple tests dealing with different contexts. `getPrototypeOf` seems interesting, but some random simple functions like `isFrozen` or `defineProperty` would be nice to have too.