<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<script>
function boom()
{
document.getElementById("x").appendChild(document.createElementNS("http://www.w3.org/1999/xhtml", "span"));
}
</script>
</head>
<body onload="boom();">
<div style="-moz-column-count: 15;"><div style="-moz-column-count: 15;" id="x"><td style="display: block; height: 2.5em;"></td></div></div>
</body>
</html>