<HEAD>
<SCRIPT src=tableDom.js>
</SCRIPT>
<SCRIPT>

function doIt() {
  var table = document.getElementsByTagName("TABLE")[0];
  var cg = document.createElement("COLGROUP", null);
  cg.width=200
  var col = document.createElement("COL", null);
  cg.appendChild(col);
  col = document.createElement("COL", null);
  cg.appendChild(col);
  table.appendChild(cg);
}
</SCRIPT>  
</HEAD>
<BODY onload="doIt()">
<table bgcolor=orange border>
 <colgroup>
  <col width=100>
 </colgroup>
 <tr>
  <td>col-100</td><td>cg-200</td><td>cg-200</td>
 </tr>
</table>
</BODY></HTML>