iframe自适应高度

<iframe id="frame_content" src="iframe_b.html" scrolling="no" frameborder="0" onload="this.height=100"></iframe>
    <script type="text/javascript">
    function reinitIframe(){
    var iframe = document.getElementById("frame_content");
    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>