<html>
<head>
<script>

function boom()
{
  var col = document.createElement("col");
  col.setAttribute('span', 2);
  document.body.appendChild(col);
  col.removeAttribute('span');
  document.body.offsetHeight;
  document.body.removeChild(col);
}

</script>
</head>

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

</html>