废话少说,直接奉上示例代码:
<script type="text/javascript"> function EventUtil() { var _self = this; ///添加事件 var addEvent = (function () { if (document.addEventListener) { return function (el, type, fn) { el.addEventListener(type, fn, false); } } else { return function (el, type, fn) { el.attachEvent("on" + type, function () { return fn.call(el, window.event); }); } } })(); ///添加属性改变事件 var addPropertyChangeEvent = function (obj, fn) { if (window.ActiveXObject) { obj.onpropertychange = fn; } else { obj.addEventListener("input", fn, false); } } //移除事件 var removeEvent = function (obj, type, fn) { if (obj.removeEventListener) { obj.removeEventListener(type, fn, false); } else if (obj.detachEvent) { obj.detachEvent("on" + type, obj["on" + type + fn]); obj["on" + type + fn] = null; } } //加载事件 var loadEvent = function (fn) { var oldonload = window.onload; if (typeof oldonload != "function") { window.onload = fn; } else { window.onload = function () { oldonload(); fn(); } } } //阻止事件 var stopEvent = function (e) { e = e || window.event; if (e.preventDefault) { e.preventDefault(); e.stopPropagation(); } else { e.returnValue = false; e.cancelBubble = true; } } //如果仅仅是阻止事件冒泡 var stopPropagation = function (e) { e = e || window.event; if (!+"\v1") { e.cancelBubble = true; } else { e.stopPropagation(); } } //取得事件源对象 var getEvent1 = function (e) { e = e || window.event; var obj = e.srcElement ? e.srcElement : e.target; return obj; } //取得事件源对象 var getEvent2 = function (e) { if (window.event) return window.event; var c = getEvent2.caller; while (c.caller) { c = c.caller; } return c.arguments[0]; } //或者这个功能更强大 var getEvent3 = function (e) { var e = e || window.event; if (!e) { var c = this.getEvent3.caller; while (c) { e = c.arguments[0]; if (e && (Event == e.constructor || MouseEvent == e.constructor)) { break; } c = c.caller; } } var target = e.srcElement ? e.srcElement : e.target, currentN = target.nodeName.toLowerCase(), parentN = target.parentNode.nodeName.toLowerCase(), grandN = target.parentNode.parentNode.nodeName.toLowerCase(); return [e, target, currentN, parentN, grandN]; }_self.addEvent = addEvent; _self.addPropertyChangeEvent = addPropertyChangeEvent; _self.removeEvent = removeEvent; _self.loadEvent = loadEvent; _self.stopEvent = stopEvent; _self.stopPropagation = stopPropagation; _self.getEvent1 = getEvent1; _self.getEvent2 = getEvent2; _self.getEvent3 = getEvent3; } var eventUtil = new EventUtil(); eventUtil.loadEvent(function () { eventUtil.addEvent(document, "click", function (e) { alert(eventUtil.getEvent3(e)); }); eventUtil.addPropertyChangeEvent(document,function(e){ alert(eventUtil.getEvent3(e)); }); }); </script>
javascript事件处理分为三个阶段:捕获 - 处理 - 起泡。
以点击按钮为例:
捕获阶段:由外层到内层,首先调用给Window注册的click捕获阶段监听方法,然后document、body、一层层的父节点,一直到按钮本身。
处理阶段:调用按钮本身的click监听方法。
起泡阶段:从按钮开始,从内层到外层,依次调用各级父节点的起泡阶段监听方法,直到Window。
但是,对于IE8及更低版本IE,不支持捕获阶段,因此捕获阶段的事件监听目前尚不通用。
通常的事件处理方法形式为:
function eventHandler(e) { e = e || window.event; var target = e.target || e.srcElement; ... ... }
e为事件对象,当事件触发时,作为参数传进来,但对于IE8及更低版本IE不适用,只能通过全局的event变量访问,好在不会出现同时处理两个事件的情况。