var xmlhttp = GetXmlHttpObject();
//var q = Math.random();
var d = new Date();
var starttime = (new Date()).getTime();
//alert(starttime);
var msec = 5000;
var LogInterval = window.setInterval("logData();", msec);

function logData()
{
	//alert(starttime);
	if (xmlhttp==null)
	{		
		return;
	}
	var url="onpagelogger.php";
	url=url+"?st="+document.body.scrollTop;
	var nsec = parseInt(((new Date()).getTime()-starttime)/1000.0);
	url+="&sec="+nsec;
	url+="&sid="+Math.random();
	//alert (url);
	xmlhttp.open("GET",url,true);
	xmlhttp.send(null);
	//alert("mfdsf");

	
	if(nsec>=60 && msec==5000){		
		//alert ('dsd');
		window.clearInterval(LogInterval);
		msec = 10000;
		LogInterval = window.setInterval("logData();", msec);
	}else if(nsec>=120 && msec==10000){
		window.clearInterval(LogInterval);
		msec = 20000;
		LogInterval = window.setInterval("logData();", msec);
	}else if(nsec>=300 && msec==20000){
		window.clearInterval(LogInterval);
		msec = 60000;
		LogInterval = window.setInterval("logData();", msec);
	}
}
	
function GetXmlHttpObject()
{	
	if (window.XMLHttpRequest)
  	{
  		return new XMLHttpRequest();
  	}
	if (window.ActiveXObject)
  	{
		return new ActiveXObject("Microsoft.XMLHTTP");
  	}
	return null;
}