iframe的动态调整高度IE8

//parent.document.getElementById('mainFrame').style.height=document.body.scrollHeight;var iframe = parent.document.getElementById('mainFrame');if(navigator.userAgent.indexOf("MSIE")>0){iframe.style.height=document.body.scrollHeight;}else if(navigator.userAgent.indexOf("Firefox")>0){alert("请使用IE浏览器！\n如有疑问请联系管理员qq:630156797");iframe.height=document.documentElement.scrollHeight;//FireFox}else if(navigator.userAgent.indexOf("Chrome")>0){alert("请使用IE浏览器！\n如有疑问请联系管理员qq:630156797");iframe.height=document.documentElement.scrollHeight;//FireFox}else{alert("未识别的浏览器类型，如有疑问请联系管理员qq:630156797 \n"+navigator.userAgent);}?

将其命名为bottom.js
<script for="window" event="onload" src="/sfda/js/bottom.js" language="JavaScript" type="text/javascript">
</script>