iframe自适应内容高度

<iframe src="www.pjkui.com" id="reply" frameBorder="0"
                        scrolling="no" width="100%" onload="setHight()"
                        >
               
                </iframe>
                 <script type="text/javascript" language="jacascript">
                     function setHight(){
                     var ifm=document.getElementById("reply");
                     var subWeb=ifm.contentDocument;
                     ifm.height=subWeb.body.scrollHeight;
                     }
                     
                </script>