iframe通过js自动调节高度

<script type="text/javascript">
function autoResize()
{
    try
    {
        document.all["content"].style.height = content.document.body.scrollHeight;
    }
    catch(e){

    }
}
</script> 
        <iframe id="content" name="content" frameborder="0" marginwidth="0" marginheight="0" scrolling="no"style="width:100%;aho:expression(autoResize())"></iframe>