var xmlHttp
function updateStudents(){ 
	xmlHttp=GetXmlHttpObject()
	if(xmlHttp==null){
		//alert ("Browser does not support HTTP Request")
		return
	}
	var url="doupdate.php"
	url=url+"?sid="+Math.random()
	xmlHttp.onreadystatechange=stateChanged 
	xmlHttp.open("GET",url,true)
	xmlHttp.send(null)
}

function stateChanged() { 
	if(xmlHttp.readyState==4 || xmlHttp.readyState=="complete"){ 
  		//document.getElementById("checkid").innerHTML=xmlHttp.responseText 
 	}
}

function GetXmlHttpObject(){
	var xmlHttp=null;
	try{
		// Firefox, Opera 8.0+, Safari
		xmlHttp=new XMLHttpRequest();
 	}
	catch (e){
 		//Internet Explorer
		try{
			xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
		}
		catch(e){
			xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
		}
	}
	return xmlHttp;
}