有效状态机

 var ctrl1 = {
      activate: function() {
           console.log("ctrl1-active");
      },
      deactivate: function() {
           console.log("ctrl1-deactive");
      }
};
 var ctrl2 = {
      activate: function() {
           console.log("ctrl2-active");
      },
      deactivate: function() {
           console.log("ctrl2-deactive");
      }
};
 var ctrl3 = {
      activate: function() {
           console.log("ctrl3-active");
      },
      deactivate: function() {
           console.log("ctrl3-deactive");
      }
};

function Statemachine() {};

var extend = (function() {
    var F = function() {};
    return function(C, P) {
        F.prototype = P.prototype;
        C.prototype = new F();
        C.uper = P;
        C.prototype.constructor = C;
    };
})();

// EventProxy is an Event.js
extend(Statemachine, EventProxy);
Statemachine.fn = Statemachine.prototype;
Statemachine.fn.add = functino(controller) {
    this.on("change", function(current) {
         if (controller == current) {
               controller.activate();
         } else {
               controller.deactivate();
         }
    });

    contrlller.active = function() {
         this.trigger("change", controller);
    }.bind(this);
};

var  sm = new Statemachine;
sm.add(ctrl1);
sm.add(ctrl2);
sm.add(ctrl3);

ctrl1.active(); // sm.trigger("change", ctrl1);