JS自定义事件原生

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=0; start<length; start+=1) {
                //改变this指向
                this._listener[type][start].call(this, events);
            }
        }
        return this;
    },
    fireEvents: function(array) {
        if (array instanceof Array) {
            for (var i=0, length = array.length; i<length; i+=1) {
                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=0, length=listeners.length; i<length; i+=1){
                    if (listeners[i] === key){
                        listeners.splice(i, 1);
                        break;
                    }
                }
            } else if (key instanceof Array) {
                for (var lis=0, lenkey = key.length; lis<lenkey; lis+=1) {
                    this.removeEvent(type, key[lenkey]);
                }
            } else {
                delete this._listener[type];
            }
        }
        return this;
    },
    removeEvents: function(params) {
        if (params instanceof Array) {
            for (var i=0, length = params.length; i<length; i+=1) {
                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！");    
    }
});

document.onclick = function(e) {
    e = e || window.event;
    var target = e.target || e.srcElement;
    if (!target || !/input|pre/i.test(target.tagName)) {
        myEvents.fireEvents(["once", "infinity"]);
    }
};

var $ = function(el) {
    return new $.init(el);
};
$.init = function (el) {
    this.el = (el && el.nodeType == 1)? el: document;
};

$.init.prototype = {
    constructor: this,
    addEvent: function(type, fn, capture) {
        var el = this.el;
        if (window.addEventListener) {
            el.addEventListener(type, fn, capture);
            var ev = document.createEvent("HTMLEvents");
            ev.initEvent(type, capture || false, false);

            if (!el["ev" + type]) {
                el["ev" + type] = ev;
            }
        } else if (window.attachEvent) {
            el.attachEvent("on" + type, fn);
            if (isNaN(el["cu" + type])) {
                // 自定义属性
                el["cu" + type] = 0;
            }
            var fnEv = function(event) {
                if (event.propertyName == "cu" + type) { fn.call(el); }
            };
            el.attachEvent("onpropertychange", fnEv);
            if (!el["ev" + type]) {
                el["ev" + type] = [fnEv];
            } else {
                el["ev" + type].push(fnEv);
            }
        }
        return this;
    },
    fireEvent: function(type) {
        var el = this.el;
        if (typeof type === "string") {
            if (document.dispatchEvent) {
                if (el["ev" + type]) {
                    el.dispatchEvent(el["ev" + type]);
                }
            } else if (document.attachEvent) {
                el["cu" + type]++;
            }
        }
        return this;
    },
    removeEvent: function(type, fn, capture) {
        var el = this.el;
        if (window.removeEventListener) {
            el.removeEventListener(type, fn, capture || false);
        } else if (document.attachEvent) {
            el.detachEvent("on" + type, fn);
            var arrEv = el["ev" + type];
            if (arrEv instanceof Array) {
                for (var i=0; i<arrEv.length; i+=1) {
                    el.detachEvent("onpropertychange", arrEv[i]);
                }
            }
        }
        return this;
    }
};

var fnClick = function(e) {
    e = e || window.event;
    var target = e.target || e.srcElement;

    if (target.nodeType === 1) {
        alert("点击类型：" +  e.type);
        $(target).fireEvent("alert");
    }
}, funAlert1 = function() {
    alert("自定义alert事件弹出！");    
}, funAlert2 = function() {
    alert("自定义alert事件再次弹出！");    
};

// 测试用的张小姐图片
var elImage = document.getElementById("image");
$(elImage)
    .addEvent("click", fnClick)
    .addEvent("alert", funAlert1)
    .addEvent("alert", funAlert2);

// 删除自定义事件按钮
var elButton = document.getElementById("button");
$(elButton).addEvent("click", function() {
    $(elImage)
        .removeEvent("alert", funAlert1)
        .removeEvent("alert", funAlert2);    

    alert("清除成功！");
});