params="";

  function make_url_request(url) {
    if (window.XMLHttpRequest) {
      xmlhttp = new XMLHttpRequest();
      xmlhttp.open("GET",url,false);
      xmlhttp.send(null);
    } else if (window.ActiveXObject) {
      xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
      if (xmlhttp){
        xmlhttp.open("GET",url,false);
        xmlhttp.send();
      }
    } else {
      var t_img = new Image();
      t_img.src = url;
    }
  }

  function tracker() {
      if(params && params != '') {make_url_request("/tracker.php?"+params);}
  }

  function registerUnpaidClick() {
      make_url_request("/tracker.php?unpaidClick=1&"+params);
  }