<html>
<head>
<script>
function SetCwinHeight(obj)
{
var cwin=obj;
if (document.getElementById)
{
if (cwin && !window.opera)
{
if (cwin.contentDocument && cwin.contentDocument.body.offsetHeight)
cwin.height = cwin.contentDocument.body.offsetHeight + 20; //FF NS
else if(cwin.Document && cwin.Document.body.scrollHeight)
cwin.height = cwin.Document.body.scrollHeight + 10;//IE
}
else
{
if(cwin.contentWindow.document && cwin.contentWindow.document.body.scrollHeight)
cwin.height = cwin.contentWindow.document.body.scrollHeight;//Opera
}
}
}
</script>
</head>
<body>
<iframe src="http://www.cnblogs.com/" onload="SetCwinHeight(this);" width="100%" height="100%">
</body>
</html>
原文：http://www.cnblogs.com/benu/p/4166813.html