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 id if (item.id && item.id === elmName.split('#')[1]) { return true; } } if (elmName.split('.')[1]) { //by class if (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 ie if (!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 ie if (!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>1</button></li> <li><button>2</button></li> <li><button>3</button></li> <li><button>4</button></li> <li><button>5</button></li> </ul> <button>取消绑定</button> </div> <p></p> <script src="https://www.jb51.net/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>
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