<!DOCTYPE HTML> <html> <head> <script type="text/javascript"> function init() { // This will throw a HierarchyRequestError exception var doc = document.implementation.createDocument(null, 'DOC', null); doc.documentElement.appendChild(doc); } window.addEventListener("load", init, false); </script> </head> <body> Testcase for bug 415498. This page should show an exception in Error Console on load </body>