<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<script type="text/javascript">

function boom()
{
  var XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
  var listbox = document.createElementNS(XUL_NS, 'listbox');
  document.body.appendChild(listbox);
  listbox.appendChild(document.createElementNS(XUL_NS, 'listitem'));
  listbox.appendChild(document.createElementNS(XUL_NS, 'listboxbody'));
  listbox.appendChild(document.createElementNS(XUL_NS, 'hbox'));
}

</script>
</head>

<body onload="boom();"></body>
</html>