function createXmlHttpObject() {
  var req = null;
  try {
    req = new XMLHttpRequest(); //ie7, ff, safari
  }
  catch (e) {
    try {
      req = new ActiveXObject("Msxml2.XMLHTTP"); //later ie
    }
    catch (e) {
      try {
        req = new ActiveXObject("Microsoft.XMLHTTP") // earlier ie
      }
      catch (e) {
        // could not create XMLHttpRequest object
        return false;
      }
    }
  }
  return req;
}