iframe根据内容自动伸缩

function SetCwinHeight()
{
var cwin=document.getElementById("cwin");
if (document.getElementById)
{
if (cwin && !window.opera)
{
if (cwin.contentDocument && cwin.contentDocument.body.offsetHeight)
cwin.height = cwin.contentDocument.body.offsetHeight;
else if(cwin.Document && cwin.Document.body.scrollHeight)
cwin.height = cwin.Document.body.scrollHeight;
}
}
}

最后，加入iframe,不能丢掉onload属性，当然了，id也必须也函数中的cwin匹配

<iframe width="778" align="center" height="200" id="cwin" name="cwin" onload="Javascript:SetCwinHeight()" frameborder="0" scrolling="no"></iframe>