<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<script>
<![CDATA[

function boom()
{
  document.documentElement.offsetHeight;
  var div = document.createElementNS("http://www.w3.org/1999/xhtml", "div");
  div.style.cssFloat = "left";
  document.getElementById("a").appendChild(div);
}

]]>
</script>
</head>
<body onload="boom();">
<fieldset id="a"><legend style="display: table-footer-group;"></legend></fieldset>
</body>
</html>