只刷新某一个TD里的内容

代码:

<script language=JavaScript>
function change(s){
var tmpobj=document.getElementById(s);
var d=new Date();
tmpobj.innerHTML=s+'-'+d.getTime();
}
</script>
<table>
 <tr>

  <td id="td1">old1
  </td>
 </tr>
 <tr>
  <td id="td2">old2
  </td>
 </tr>
 <tr>
 <td><a href="JavaScript:change('td1');">link1</a>&nbsp;<a href="JavaScript:change('td2');">link2</a>
 </td>
 </tr>
</table>