var xmlHttp
function get_checked(str,field,argurl)
{ 
xmlHttp=GetXmlHttpObject()
if (xmlHttp==null)
{
alert ("Browser does not support HTTP Request")
return
} 
var url=argurl
url=url+"?selectId="+str
url=url+"&item="+field
url=url+"&sid="+Math.random()


if(field=='check_username')
xmlHttp.onreadystatechange=check_user;
xmlHttp.open("GET",url,true)
xmlHttp.send(null)


}

function check_user() 
{ 
	if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete")
	{ 
	
	if(xmlHttp.responseText!="")
		{		   
			document.getElementById("checkuser").innerHTML='Username already exists.';
			document.getElementById("username").value='';
		}else
		{
			document.getElementById("checkuser").innerHTML="";
		}
		
	} 
}




function GetXmlHttpObject()
{ 
	var objXMLHttp=null
if (window.XMLHttpRequest)
{
	objXMLHttp=new XMLHttpRequest()
}
else if (window.ActiveXObject)
{
	objXMLHttp=new ActiveXObject("Microsoft.XMLHTTP")
}
	return objXMLHttp
}