function extUserStats(track) {
  if (window.innerWidth) {
    var viewx = window.innerWidth;
    var viewy = window.innerHeight;
  }
  else {
    var viewx = document.documentElement.clientWidth;
    var viewy = document.documentElement.clientHeight;
  }
  
  if (window.XMLHttpRequest) { // Mozilla, Safari, ...
      http_request = new XMLHttpRequest();
  } else if (window.ActiveXObject) { // IE
      http_request = new ActiveXObject("Microsoft.XMLHTTP");
  }
  http_request.open('GET', track + 'userstats.php?viewx='+viewx+'&viewy='+viewy+'&resx='+screen.width+'&resy='+screen.height+'&depth='+window.screen.colorDepth, true);
  http_request.send(null);
}