function createRequest() {
	try {request = new XMLHttpRequest();}
	catch (trymicrosoft) {
		try {request = new ActiveXObject("Msxml2.XMLHTTP");}
		catch (othermicrosoft) {
			try {request = new ActiveXObject("Microsoft.XMLHTTP");}
		catch (failed) {request = false;}
		}}}

function sendRequest(){
	createRequest();
	url = "track.php?id=time_utc";
	request.open("POST", url, true);
	request.setRequestHeader("Method", "POST URL HTTP/1.1");
	//request.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
	request.onreadystatechange = GetServerTime;
	request.send('');}

function GetServerTime(){
	if (request.readyState == 4){
		TimeServer = (request.responseText);
		TimeClient = (new Date()).getTime();
		TimeDelta = TimeServer - TimeClient;
		setTimeout("sendRequest()", 180000);}}