function setupReqObject(listener, url, newThread) {
  // newThread - pass in true if it should run on separate thread  
  //             pass in false if it should run on same thread as browser event thread
    if (window.XMLHttpRequest){ // Non-IE browsers
      reqObj = new XMLHttpRequest();
      reqObj.onreadystatechange = listener;
      try {
      	reqObj.open("GET", url, newThread); 
      } catch (e) {
         alert("Cannot connect to server");
      }
      reqObj.send(null);
    } else if (window.ActiveXObject) { // IE      
      reqObj = new ActiveXObject("Microsoft.XMLHTTP");
      if (reqObj) {
        reqObj.onreadystatechange = listener;
        reqObj.open("GET", url, newThread);
       }
    }
  }