图片发自简书App

//自定义事件
var $ = function(el){
return new _$(el);
}
var _$ = function(el){
this.el = (el&&el.nodeType == 1)?el: document;
}
_$.prototype = {
constructor: _$,
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);
//在元素上存储创建的事件，方便自定义事件的触发
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，触发事件
el["cu" + type] = 0;
}
var fnEv = function(event){
if(event.prototyName == "cu"+type){
fn.call(el);
}
}
el.attachEvent("onpropertychange", fnEv);
//在元素上存储绑定的propertychange事件，方便删除
if(!el["el" + 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) {
//改变自定义属性，触发自定义事件
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.detachEvent) {
el.detachEvent( "on" + type,fn);
var arrEv = el["ev" + type];
if(arrEv instanceof Array){
for (var i = 0; i < arrEv.length; i+=1) {
//删除方法名下所有绑定的propertychange事件
el.detachEvent("onpropertychange" , arrEv[i]);
}
}
}
return this;
}
}