iframe的老问题，动态调整，那位大虾有办法，求教（内详）

<style>
.SwitchClass{color:black;cursor:hand;font-family:webdings;font-size:9pt}
</style>
<body>
<script language="javascript">
function SwitchMenuStatus()
{
if(SwitchMenu.innerText==3)
{
SwitchMenu.innerText=4;
document.all("Menu").style.display="none";
}
else
{
SwitchMenu.innerText=3;
document.all("Menu").style.display="";
}
}
function OpenMenu()
{
if(SwitchMenu.innerText==4)
{
SwitchMenu.innerText=3;
document.all("Menu").style.display="";
}
else
{
SwitchMenu.innerText=3;
document.all("Menu").style.display="";
}
}</script>
<table width="100%" border="1" cellpadding="3" cellspacing="0" height="100%" bordercolor="#EEEEEE" bordercolordark="#FFFFFF" bordercolorlight="#999999">  
  <tr>
    <td id=Menu name="Menu" vAlign=top align=left>
      <iframe src="about:blank" style="height:100%;visibility:inherit;width:100" border="0" frameborder=0></iframe>
    </td>         
    <td width="5" height="100%" onmouseover="OpenMenu();">
      <table border=0 cellPadding=0 cellSpacing=0>
        <tr> 
  <td style="height: 100%" valign=middle onclick="SwitchMenuStatus();">
            <span class=SwitchClass id=SwitchMenu title="关闭/打开菜单">3</span>
          </td>
        </tr>
      </table>
    </td>
    <td id=Home name="Home" vAlign=top align=left width="100%">
      <iframe src="about:blank" style="height:100%;visibility:inherit;width:100%" border="0" frameborder=0></iframe>
    </td>
  <tr>
</table>