Iframe自适应高度绝对好使的代码 兼容IE,遨游，火狐

<script type="text/javascript">
function reinitIframe(){
var iframe = document.getElementById("mainFrame");
try{
var bHeight = iframe.contentWindow.document.body.scrollHeight;
var dHeight = iframe.contentWindow.document.documentElement.scrollHeight;
var height = Math.max(bHeight, dHeight);
iframe.height = height;
}catch (ex){}
}
window.setInterval("reinitIframe()", 200);
</script>