1<html xmlns="http://www.w3.org/1999/xhtml">
2<head>
3<script>
4function boom()
5{
6  document.getElementById("c").setAttribute('span', 2);
7  document.getElementById("cg").setAttribute('span', 2);
8}
9</script>
10</head>
11<body onload="boom();">
12<table><colgroup id="cg"><col span="3" id="c" /></colgroup></table>
13</body>
14</html>
15