iframe框架自适应网页高度

<script language="javascript">
<!--
function setFrameHeight(obj){
var win=obj;
if (document.getElementById)
{
if (win && !window.opera)
{
   if (win.contentDocument && win.contentDocument.body.offsetHeight)

    win.height = win.contentDocument.body.offsetHeight+"px";
   else if(win.Document && win.Document.body.scrollHeight)
    win.height = win.Document.body.scrollHeight+"px";
}
}
}
-->
</script>

<iframe id="main" style="width:100%;" name="main" src=http://www.g.cn/ scrolling="no" frameborder="0" marginheight="0" marginwidth="0" onload="Javascript:setFrameHeight(this)"></iframe>
<br><br style="overflow: hidden; line-height: 10px">