js 事件调度

 var EventTarget = function () {
        this._listener = {};
    };
    EventTarget.prototype = {
        constructor: this,
        addEvent: function (type, fn) {
            if (typeof type === "string" && typeof fn === "function") {
                if (typeof this._listener[type] === "undefined") {
                    this._listener[type] = [fn];
                } else {
                    this._listener[type].push(fn);
                }
            }
            return this;
        },
        addEvents: function (obj) {
            obj = typeof obj === "object" ? obj : {};
            var type;
            for (type in obj) {
                if (type && typeof obj[type] === "function") {
                    this.addEvent(type, obj[type]);
                }
            }
            return this;
        },
        fireEvent: function (type) {
            if (type && this._listener[type]) {
                //event参数设置
                var events = {
                    type: type,
                    target: this
                };

                for (var length = this._listener[type].length, start = ; start < length; start += ) {
                    //改变this指向
                    this._listener[type][start].call(this, events);
                }
            }
            return this;
        },
        fireEvents: function (array) {
            if (array instanceof Array) {
                for (var i = , length = array.length; i < length; i += ) {
                    this.fireEvent(array[i]);
                }
            }
            return this;
        },
        removeEvent: function (type, key) {
            var listeners = this._listener[type];
            if (listeners instanceof Array) {
                if (typeof key === "function") {
                    for (var i = , length = listeners.length; i < length; i += ) {
                        if (listeners[i] === key) {
                            listeners.splice(i, );
                            break;
                        }
                    }
                } else if (key instanceof Array) {
                    for (var lis = , lenkey = key.length; lis < lenkey; lis += ) {
                        this.removeEvent(type, key[lenkey]);
                    }
                } else {
                    delete this._listener[type];
                }
            }
            return this;
        },
        removeEvents: function (params) {
            if (params instanceof Array) {
                for (var i = , length = params.length; i < length; i += ) {
                    this.removeEvent(params[i]);
                }
            } else if (typeof params === "object") {
                for (var type in params) {
                    this.removeEvent(type, params[type]);
                }
            }
            return this;
        }
    };

    var myEvents = new EventTarget();
    myEvents.addEvents({
        "once": function () {
            alert("该弹框只会出现一次！");
            this.removeEvent("once");
        },
        "infinity": function () {
            alert("每次点击页面，该弹框都会出现！");
        }
    });

    myEvents.fireEvents(["once", "infinity"]);