<table border=1 id=ys>
<tr>
<td>1</td><td>1</td>
</tr>
<tr>
<td>2</td><td>2</td>
</tr>
<tr>
<td>3</td><td>3</td>
</tr>
</table>
<input type=button name=ok onclick=yunshui(ys)>
<script language=JavaScript>
function yunshui(id){
var newTR = id.childNodes[0].childNodes[0].cloneNode(true);
id.childNodes[0].insertAdjacentElement("beforeEnd",newTR);
id.childNodes[0].childNodes[0].removeNode(true);
}
</script>