var server_time = 0;

function veilingSynchronizeTime() {

	var date = new Date();

	var startTime = Math.round(date.getTime()/1000);

	// verbinding maken
	if (window.ActiveXObject) {
		var http2 = new ActiveXObject("Microsoft.XMLHTTP");
	} else if (window.XMLHttpRequest) {
		var http2 = new XMLHttpRequest();
	}
	
	http2.open('get', '/veiling/veilingSynchronizeTime?rnd='+Math.round(1000000*Math.random()),true);
	http2.onreadystatechange = function() {
		if ((http2.readyState == 4) || (http2.readyState == "complete")) {
	
			var new_time = parseInt(http2.responseText);
	
			if (isNaN(new_time))
				return;

			var date = new Date();
			var end_time =  Math.round(date.getTime()/1000);			

			// calculate new time
			new_time += Math.round((end_time - startTime) / 2);
		
			if (server_time != new_time) {
	
				// bereken verschil
				var diff = new_time - server_time;
	
				server_time = new_time;
	
				// tel verschil op bij timers
				for (var index in tijd_verschil)
					tijd_verschil[index] -= diff;
			}

		};
	}
	
	http2.send(null);

}