方案一：

<iframe src=”http://www.alixixi.com/index.htm” name=”content” id=”content” allowtransparency=”true” align=”default” marginwidth=0 marginheight=0 frameborder=0 scrolling=no height=”200″ width=”500″ onload=”this.height=0;var fdh=(this.Document?this.Document.body.scrollHeight:this.contentDocument.body.offsetHeight);this.height=(fdh>200?fdh:200)//code by Tencent.nokersang”>This message is only visible to older browsers.</iframe>

方案二：

<script language=javascript>
function iframeAutoFit()
{
try
{
if(window!=parent)
{
var a = parent.document.getElementsByTagName(”IFRAME”);
for(var i=0; i<a.length; i++) //author:meizz
{
if(a[i].contentWindow==window)
{
var h = document.body.scrollHeight;
if(document.all) {h += 4;}
if(window.opera) {h += 1;}
a[i].style.height = h;
}
}
}
}
catch (ex)
{
alert(”脚本无法跨域操作！”);
}
}
if(document.attachEvent) window.attachEvent(”onload”, iframeAutoFit);
else window.addEventListener(’load’, iframeAutoFit, false);
</script>