找了很久,这个终于能用了

放到<head>区:

<script language=”Javascript”>
var getFFVersion=navigator.userAgent.substring(navigator.userAgent.indexOf(“Firefox”)).split(“/”)[1]
//extra height in px to add to iframe in FireFox 1.0+ browsers
var FFextraHeight=getFFVersion>=0.1? 16 : 0

function dyniframesize(iframename) {
var pTar = null;
if (document.getElementById){
pTar = document.getElementById(iframename);
}
else{
eval(‘pTar = ‘ + iframename + ‘;’);
}
if (pTar && !window.opera){
//begin resizing iframe
pTar.style.display=”block”

if (pTar.contentDocument && pTar.contentDocument.body.offsetHeight){
//ns6 syntax
pTar.height = pTar.contentDocument.body.offsetHeight+FFextraHeight;
}
else if (pTar.Document && pTar.Document.body.scrollHeight){
//ie5+ syntax
pTar.height = pTar.Document.body.scrollHeight;
}
}
}
</script>

Iframe的写法:

<iframe frameborder=”0″ width=”100%” scrolling=”no” name=”faculty” id=”myTestFrameID” onload=”javascript:{dyniframesize(‘myTestFrameID’);}” marginwidth=0 marginheight=0></iframe>