[请教]菜单收缩脚本怎么写？（急~~）

Question

<script>
function showtable(n){
  var table = document.getElementById("table"+n);
  table.style.display = table.style.display=="none"?"":"none";
}
</script>

Answer 1

<table width="150" border="0" align="center" cellpadding="0" cellspacing="0">
  <tr> 
    <td height="25" bgcolor="#6699CC"><table width="150" border="0" align="center" cellpadding="0" cellspacing="2" style="cursor:hand;" onClick="showtable(1)">
        <tr> 
          <td valign="middle">A</td>
        </tr>
      </table></td>
  </tr>
  <tr> 
    <td><table id="table1" width="150" border="0" align="center" cellpadding="0" cellspacing="2" bgcolor="#EFEFEF">
        <tr> 
          <td>111</td>
        </tr>
      </table></td>
  </tr>
</table>
<table width="150" border="0" align="center" cellpadding="0" cellspacing="0">
  <tr> 
    <td height="25" bgcolor="#6699CC"><table width="150" border="0" align="center" cellpadding="0" cellspacing="2" style="cursor:hand;" onClick="showtable(2)">
        <tr> 
          <td valign="middle">B</td>
        </tr>
      </table></td>
  </tr>
  <tr> 
    <td><table id="table2" width="150" border="0" align="center" cellpadding="0" cellspacing="2" bgcolor="#EFEFEF">
        <tr> 
          <td>22</td>
        </tr>
      </table></td>
  </tr>
</table>
<script>
function showtable(id)
{
if(eval('document.getElementById("table'+id+'").style.display=="none"'))
   {
   eval('document.getElementById("table'+id+'").style.display=""'); 
   }
else
   {
   eval('document.getElementById("table'+id+'").style.display="none"'); 
   }
}
</script>完整代码