phodal/lettuce

var Event = {
    on: function(event, callback){
        this._events = this._events || {};
        this._events[event] = this._events[event] || [];
        this._events[event].push(callback);
    },
    off: function(event, callback){
        this._events = this._events || {};
        if (event in this._events === false) {
            return;
        }
        this._events[event].splice(this._events[event].indexOf(callback), 1);
    },
    trigger: function(event,data){  // 触发时传入的数据，加一个data便于理解，可读性更强 
        this._events = this._events || {};
        if (event in this._events === false) {
            return;
        }
        for (var i = 0; i < this._events[event].length; i++) {
            this._events[event][i].apply(this, Array.prototype.slice.call(arguments, 1));
        }
    }
};

var event = {
    Event: Event
};


Lettuce.prototype = Lettuce.extend(Lettuce.prototype, event);