try:
<script>
document.onclick=insert;function insert(){
var e=event.srcElement;
if((e.tagName=="TD")&&e){
e.parentElement.insertCell(e.cellIncex+1).innerText="new";
}
}
</script>
<div align="center">
  <center>
  <table border="1" width="100">
    <tr>
      <td width="50%">0</td>
      <td width="50%">1</td>
    </tr>
    </table>
  </center>
</div>