实现一个简单的on和off方法
介绍:Event对象:
funcList: {}, //保存delegate所绑定的方法
ieFuncList :{} //保存ie下的绑定方法
Event 对象中的 on, off 方法,主要调用
Event.addEvent, Event.delegateHandle这两个方法
Event.addEvent: 调用底层的addEventListener添加监听事件
Event.delegateHandle: 当发生事件之后,随着事件的冒泡上升,判断存在事件委托的元素,并执行对应的回调函数
addEvent / offEvent:
obj.addEventListener(type, fn, false);
obj.removeEventListener(type, fn, false);
代码-Event.js/** * addEvent * author laynezhou@tencent.com */window.Event = {};var Event = {funcList: {}, //保存delegate所绑定的方法ieFuncList: {}, //由于保存在ie下绑定的方法on: function(obj, selector, type, fn) {if (!obj || !selector) return false;var fnNew = Event.delegateHandle(obj, selector, fn);Event.addEvent(obj, type, fnNew);/* 将绑定的方法存入Event.funcList,以便之后解绑操作 */if (!Event.funcList[selector]) {Event.funcList[selector] = {};}if (!Event.funcList[selector][type]) {Event.funcList[selector][type] = {};}Event.funcList[selector][type][fn] = fnNew;},off: function(obj, selector, type, fn) {if (!obj || !selector || !Event.funcList[selector]) {return false;}var fnNew = Event.funcList[selector][type][fn];if (!fnNew) {return;}Event.offEvent(obj, type, fnNew);Event.funcList[selector][type][fn] = null;},delegateHandle: function(obj, selector, fn) {/* 实现delegate 的转换方法,事件冒泡上升时, 符合条件时才会执行回调函数 */var func = function(event) {var event = event || window.event;var target = event.srcElement || event.target;var parent = target;function contain(item, elmName) {if (elmName.split("#")[1]) { //by idif (item.id && item.id === elmName.split("#")[1]) {return true;}}if (elmName.split(".")[1]) { //by classif (hasClass(item, elmName.split(".")[1])) {return true;}}if (item.tagName == elmName.toUpperCase()) {return true; //by tagname}return false;}while (parent) {/* 如果触发的元素,属于(selector)元素的子级。 */if (obj == parent) {return false; //触发元素是自己}if (contain(parent, selector)) {fn.call(obj, event);return;}parent = parent.parentNode;}};return func;},addEvent: function(target, type, fn) {if (!target) return false;var add = function(obj) {if (obj.addEventListener) {obj.addEventListener(type, fn, false);} else {// for ieif (!Event.ieFuncList[obj]) Event.ieFuncList[obj] = {};if (!Event.ieFuncList[obj][type]) Event.ieFuncList[obj][type] = {};Event.ieFuncList[obj][type][fn] = function() {fn.apply(obj, arguments);};obj.attachEvent("on" + type, Event.ieFuncList[obj][type][fn]);}}if (target.length >= 0 && target !== window && !target.tagName) {for (var i = 0, l = target.length; i < l; i++) {add(target[i])}} else {add(target);}},offEvent: function(target, type, fn) {if (!target) return false;var remove = function(obj) {if (obj.addEventListener) {obj.removeEventListener(type, fn, false);} else {//for ieif (!Event.ieFuncList[obj] || !Event.ieFuncList[obj][type] || !Event.ieFuncList[obj][type][fn]) {return;}obj.detachEvent("on" + type, Event.ieFuncList[obj][type][fn], false);Event.ieFuncList[obj][type][fn] = {};}}if (target.length >= 0 && target !== window && !target.tagName) {for (var i = 0, l = target.length; i < l; i++) {remove(target[i])}} else {remove(target);}},};
代码-DEMO.html<!DOCTYPE html><html><head><meta charset="utf-8"><title>test</title></head><body><p>测试 Event </p><div id=content><ul><li><button id="btn1">1</button></li><li><button id="btn2">2</button></li><li><button id="btn3">3</button></li><li><button id="btn4">4</button></li><li><button id="btn5">5</button></li></ul><button id="unbind">取消绑定</button></div><p id="text"></p><script src="addEvent.js"></script><script>(function(){/* 演示demo*/var $id=function(id){return document.getElementById(id) || id;}var outer = $id("content"),btn = $id("text");Event.on(outer,"button","click",add);Event.on(outer,"#unbind","click",remove);//动态添加一个按钮,查看是否有事件响应var newbtn = document.createElement("button");var node = document.createTextNode("new button");newbtn.appendChild(node);outer.appendChild(newbtn);function add(){var e = arguments[0] || window.event;var target = e.srcElement || e.target;console.log("target:",target);btn.innerHTML = target.innerHTML + " " + e.type;}function remove(){Event.off(outer,"button","click",add);Event.off(outer,"#unbind","click",remove);}})();</script></body></html>