if (document.images) {
  booking_ovr = new Image();
  booking_off = new Image();
   
  booking_ovr.src = "/images/b-onlinebooking-r.gif";
  booking_off.src = "/images/b-onlinebooking.gif";
  
  
  flightsearch_ovr = new Image();
  flightsearch_off = new Image();
   
  flightsearch_ovr.src = "/images/b-flightresearch-r.gif";
  flightsearch_off.src = "/images/b-flightresearch.gif";
}