jsp page iframe highly adaptive js code

The following actions are written inside body and outside form form

<iframe id="agentFrame" name="agentFrame" src="" width="0" height="0" style="display:none;" ></iframe> 
<script type="text/javascript"> 
function sethash(){ 
hashH = document.documentElement.scrollHeight; // Get your own height  
urlC = "/test.jsp"; // Settings iframeA Adj. src 
document.getElementById("agentFrame").src=urlC+"#"+hashH; // Passing Height as a Parameter  
} 
window.onload=sethash; 
</script>

test. jsp is as follows:

<%@ page contentType="text/html;charset=GBK" language="java"%> 
<script> 
function pseth() { 
var iObj = parent.parent.document.getElementById('infoFrame'); 
iObjH = parent.parent.frames["infoFrame"].frames["agentFrame"].location.hash; 
iObj.style.height = iObjH.split("#")[1]+"px"; 
} 
window.onload=pseth(); 
</script>