function click(e) {
      if (document.all) {
         if (event.button==2) {
               alert ("");
            return false;
         }
      }
      if (document.layers) {
         if (e.which==3) {
            alert ("");
            return false;
         }
      }
   }
//   if (document.layers) {
//      document.captureEvent(Event.MOUSEDOWN);
//   } 
document.onmousedown=click;