url "vrmlscript:
          function initialize()
          {
              // tell what events
              oldMask = Browser.eventMask;
              Browser.eventMask = 1<<5; // KeyDown Only...
              // add event observer
              Browser.addRoute(Browser,'event_changed',me,'onEvent');
              Browser.addRoute(me,'previous',slide_set,'previous');
              Browser.addRoute(me,'next',slide_set,'next');
          }
          function shutdown()
          {
              // remove event observer
              Browser.eventMask = oldMask;
              Browser.deleteRoute(Browser,'event_changed',me,'onEvent');
              Browser.deleteRoute(me,'previous',slide_set,'previous');
              Browser.deleteRoute(me,'next',slide_set,'next');
          }