关于iframe的自适应高度问题

贴一下代码：主页面

function ifraSyn(){
            try{
            var iframe = document.getElementById("ifra");
            if(iframe.Document){//ie自有属性
                iframe.style.height = iframe.Document.documentElement.scrollHeight+50;
            }else if(iframe.contentDocument){
                //ie,firefox,chrome,opera,safari
                var c=iframe.contentDocument.body.offsetHeight;
                iframe.height = iframe.contentDocument.body.offsetHeight+50 ;
            }
            }catch(e){

                }
            }

 

 

 

页面iframe的ID

<iframe width="600px" height="600px"  id="ifra" name="ifra" scrolling="no" onload="ifraSyn()" frameborder=0 src="<%=request.getContextPath()%>/frontend/passengerService/retreatChange.jsp"></iframe>