表格如下,具体要实现C2,C3,C4一行中:首先保持这一行的总宽度不变,然后能通过鼠标拖动来改变三个单元格所占比例,希望大拿能帮忙,在线等回复啊

<table border="1" style="height: 60px">
<tr>
<td align="center" colspan=6 bgcolor="gray">
C1</td>
</tr>
<tr>
<td align="center" colspan=2 bgcolor="gray">
C2</td>
<td align="center" colspan=2 bgcolor="gray">
C3</td>
<td align="center" colspan=2 bgcolor="gray">
C4</td>
</tr>
<tr>
<td align="center" colspan=3 bgcolor="gray">
C5</td>
<td align="center" colspan=3 bgcolor="gray">
C6</td>
</tr>
<tr>
<td align="center" colspan=6 bgcolor="gray">
C7</td>
</tr>
</table>
<tr>
<td align="center" colspan=6 bgcolor="gray">
C1</td>
</tr>
<tr>
<td align="center" colspan=2 bgcolor="gray">
C2</td>
<td align="center" colspan=2 bgcolor="gray">
C3</td>
<td align="center" colspan=2 bgcolor="gray">
C4</td>
</tr>
<tr>
<td align="center" colspan=3 bgcolor="gray">
C5</td>
<td align="center" colspan=3 bgcolor="gray">
C6</td>
</tr>
<tr>
<td align="center" colspan=6 bgcolor="gray">
C7</td>
</tr>
</table>