怎么用javascript实现表格的移动。

1<table border="1" id="tb1">
2<tr><td>aaa</td></tr>
3</table>

1<table border="1" id="tb2">
2<tr><td>bbb</td></tr>
3</table>

1<table border="1" id="tb3">
2<tr><td>ccc</td></tr>
3</table>

1<table border="1" id="tb4">
2<tr><td>ddd</td></tr>
3</table>

 1<span id="s">
 2<table border="1" id="tb1">
 3<tr><td>aaa</td></tr>
 4</table>
 5<table border="1" id="tb2">
 6<tr><td>bbb</td></tr>
 7</table>
 8<table border="1" id="tb3">
 9<tr><td>ccc</td></tr>
10</table>
11<table border="1" id="tb4">
12<tr><td>ddd</td></tr>
13</table>
14</span>

1<input onclick="s.appendChild(s.childNodes[0]);" type="submit"/>

 1<table border="1" id="ys">
 2<tr>
 3<td>1</td><td>1</td>
 4</tr>
 5<tr>
 6<td>2</td><td>2</td>
 7</tr>
 8<tr>
 9<td>3</td><td>3</td>
10</tr>
11</table>

1<input name="ok" onclick="yunshui(ys)" type="button"/>

1<script language="JavaScript">   
2function yunshui(id){   
3var newTR = id.childNodes[0].childNodes[0].cloneNode(true);   
4id.childNodes[0].insertAdjacentElement("beforeEnd",newTR);   
5id.childNodes[0].childNodes[0].removeNode(true);   
6}   
7</script>