<table>
<tr>
     <td>1.1</td>
     <td>1.2</td>
     <td>1.3</td>
</tr>
<tr id="tr1">
     <td>a</td>
     <td>b</td>
     <td>c</td>
</tr>
<tr id="tr2">
     <td>x</td>
     <td>y</td>
     <td>z</td>
</tr>
</table>
请问如何复制tr1,在后面也就是在tr2插入呢?效果如下
<table>
<tr>
     <td>1.1</td>
     <td>1.2</td>
     <td>1.3</td>
</tr>
<tr id="tr1">
     <td>a</td>
     <td>b</td>
     <td>c</td>
</tr>
<tr>
     <td>a</td>
     <td>b</td>
     <td>c</td>
</tr>
<tr id="tr2">
     <td>x</td>
     <td>y</td>
     <td>z</td>
</tr>
</table>