function loop(){

czas = 15000;

setTimeout("action()" , czas)
}

window.onload = function () {

action()

}

var xmlHttp2

function action() {

	xmlHttp2=GetXmlHttpObject2()
	if (xmlHttp2==null) {
  	alert ("Browser does not support HTTP Request")
  	return
	} 
  
	var myurl = 'up.php?time2=' +new Date().getTime();

	xmlHttp2.open("GET", myurl);
	xmlHttp2.send(null);
	
	loop();
}


function GetXmlHttpObject2()
{
var xmlHttp2=null;
try
 {
 // Firefox, Opera 8.0+, Safari
 xmlHttp2=new XMLHttpRequest();
 }
catch (e)
 {
 // Internet Explorer
 try
  {
  xmlHttp2=new ActiveXObject("Msxml2.XMLHTTP");
  }
 catch (e)
  {
  xmlHttp2=new ActiveXObject("Microsoft.XMLHTTP");
  }
 }
return xmlHttp2;
}