function include(filename) {
  var head = document.getElementsByTagName('head')[0];
  script = document.createElement('script');
  script.src = filename;
  script.type = 'text/javascript';
  head.appendChild(script);
}
function getUrlVars() {
  var vars = [], hash;
  var hashes = window.location.href.slice(window.location.href.indexOf('?') + 1) . split('&');
  for (var i = 0; i < hashes.length; i++) {
    hash = hashes[i].split('=');
    vars.push(hash[0]);
    vars[hash[0]] = hash[1];
  }
  return vars;
}
var hash = getUrlVars();
if (hash['cpa'] != '' && hash['cpa'] != null) include('/referral.php?cpa=' + hash['cpa']);