<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul" onload="boom();" class="reftest-wait"> <script type="text/javascript"> var XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"; function boom() { var A = document.getElementById("A"); var B = document.createElementNS(XUL_NS, "tabs"); var C = document.createElementNS(XUL_NS, "hbox"); B.appendChild(C); A.appendChild(B); } function remove(n) { n.parentNode.removeChild(n); } </script> <hbox id="A" onselect="remove(event.originalTarget); document.documentElement.removeAttribute('class');"></hbox> </window>