// Check to see if an XMLHttpRequest object has a 'Success' state, or not.
  // The function takes one argument, the XMLHttpRequest object
  function httpSuccess(r) {
      try {
          // If no server status is provided, and we're actually 
          // requesting a local file, then it was successful
          return !r.status && location.protocol == "file:" ||
  
              // Any status in the 200 range is good
              ( r.status >= 200 && r.status < 300 ) ||
  
              // Successful if the document has not been modified
              r.status == 304 ||
  
              // Safari returns an empty status if the file has not been modified
              navigator.userAgent.indexOf("Safari") >= 0 && typeof r.status == "undefined";
      } catch(e){}
  
      // If checking the status failed, then assume that the request failed too
      return false;
  }