js事件监听机制(事件捕获)总结(2)
整合两者的方法 function addEvent(obj,evtype,fn,useCapture) { if (obj.addEventListener) { obj.addEventListener(evtype,fn,useCapture); } else { obj.attachEvent("on"+evtype,fn);//IE不支持事件捕
整合两者的方法
function addEvent(obj,evtype,fn,useCapture) {
if (obj.addEventListener) {
obj.addEventListener(evtype,fn,useCapture);
} else {
obj.attachEvent("on"+evtype,fn);//IE不支持事件捕获
} else {
obj["on"+evtype]=fn;//事实上这种情况不会存在
}
}
function delEvent(obj,evtype,fn,useCapture) {
if (obj.removeEventListener) {
obj.removeEventListener(evtype,fn,useCapture);
} else {
obj.detachEvent("on"+evtype,fn);
} else {
obj["on"+evtype]=null;
}
}
IE的attach方法有个问题，就是使用attachEvent时在事件处理函数内部，this指向了window，而不是obj！当然，这个是有解决方案的！
但IE的attachEvent方法有另外一个问题，同一个函数可以被注册到同一个对象同一个事件上多次，解决方法：抛弃IE的 attachEvent方法吧！IE下的attachEvent方法不支持捕获，和传统事件注册没多大区别(除了能绑定多个事件处理函数)，并且IE的 attachEvent方法存在内存泄漏问题！
addEvent,delEvent现代版
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>js事件监听</title>
<style>
table td{font:12px; border-bottom:1px solid #efefef;}
</style>
</head>
<body>
<div id="outEle" style="padding:10px; border:1px solid #b2b2b2; background:#efefef;">
<input type="button" onclick="eventfun()" id="button" value="button" /><br />
<input type="button" onclick="eventfun2(this);" id="button2" value="button2" /><br />
<input type="button" id="button3" value="button3" /><br />
<input type="button" id="button4" value="button4" /><br />
<table id="htmlEleTable" width="100%" border="0" style="border:1px solid #b2b2b2; background:#fff;">
<tr id="1111"><td>111111111111111111111111111111</td></tr>
<tr id="22222"><td>222222222222222222222222222222</td></tr>
<tr id="33333"><td>333333333333333333333333333333</td></tr>
<tr id="4444"><td>444444444444444444444444444444</td></tr>
<tr id="55555"><td>555555555555555555555555555555</td></tr>
</table>
</div>
<script language="javascript" type="text/javascript">
function eventfun(){//1.直接把js方法写在页面结构上
console.log(this);//这里涉及到一个this作用域的问题，eventfun再这里是一个全局函数, 对象是window,this指向的是window
alert(this);
}
function eventfun2(eve){//在这里把事件对象作为参数传递到全局方法里
eve.name="alex";//
window.name="robin";
console.log(this);//[object Window]
console.log(eve);// [object HTMLInputElement]
console.log(this.name);// robin
console.log(eve.name);// alex
var self=eve;
console.log(this.name);//robin
console.log(self.name);//alex
alert(window.name);
alert(self.name);
}
function eventfun3(){//1.直接把js方法写在页面结构上
console.log(this);//这里涉及到一个this作用域的问题，eventfun再这里是一个全局函数, 对象是window,this指向的是window
console.log(this.id);
alert(this);
alert(this.id);
//var outEleObj = EventUtil.$("outEle");
//removeEvent(outEleObj,"click",eventfun3);
}
/*
var EventUtil = {};
EventUtil.$ = function(id){
return document.getElementById(id);
}
EventUtil.openmes = eventfun3;
EventUtil.addEventHandle = function(eventTarget,eventtype,eventHandle){//定义事件监听的对象元素,事件类型，事件函数
if(eventTarget.attachEvent){
eventTarget.attachEvent("on"+eventtype,eventHandle);
}else if(eventTarget.addEventListener){
eventTarget.addEventListener(eventtype,eventHandle,false)
}else{
eventTarget["on" + eventtype] = null;
}
};
EventUtil.deleEventHandle = function(eventTarget,eventtype,eventHandle){//定义事件监听的对象元素,事件类型，事件函数
if(eventTarget.detachEvent){
alert("on"+eventtype);
alert("on"+eventHandle);
eventTarget.detachEvent("on"+eventtype,eventHandle);
}else if(eventTarget.removeEventListener){
eventTarget.removeEventListener(eventtype,eventHandle,false)
}else{
eventTarget["on" + eventtype] = null;
}
};*/
var EventUtil={
$:function(id){
return document.getElementById(id);
},
but4fun:function(){
console.log(this);
this.addEventHandle();
},
eventfun3:function (){
console.log(this);
alert(this);
delEvent(obj,evtype,fn,useCapture);
}
}
/***使用addEventListener,attachEvent进行dom事件的监听
function addEvent(obj,evtype,fn,useCapture){
if (obj.addEventListener) {
obj.addEventListener(evtype,fn,useCapture);
}else if(obj.attachEvent){
obj.attachEvent("on"+evtype,function () {
fn.call(obj);
});
}else {
obj["on"+evtype]=fn;//事实上这种情况不会存在
}
}
function delEvent(obj,evtype,fn,useCapture) {
if (obj.removeEventListener) {
obj.removeEventListener(evtype,fn,useCapture);
} else if(obj.detachEvent){
obj.detachEvent("on"+evtype,fn);
} else {
obj["on"+evtype]=null;
}
}
function addEvent(obj,evtype,fn,useCapture) {
if (obj.addEventListener) {//优先考虑W3C事件注册方案
obj.addEventListener(evtype,fn,!!useCapture);
} else {//当不支持addEventListener时(IE),由于IE同时也不支持捕获,所以不如使用传统事件绑定
if (!fn.__EventID) {fn.__EventID = addEvent.__EventHandlesCounter++;}
//为每个事件处理函数分配一个唯一的ID
if (!obj.__EventHandles) {obj.__EventHandles={};}
//__EventHandles属性用来保存所有事件处理函数的引用
//按事件类型分类
if (!obj.__EventHandles[evtype]) {//第一次注册某事件时
obj.__EventHandles[evtype]={};
if (obj["on"+evtype]) {//以前曾用传统方式注册过事件处理函数
(obj.__EventHandles[evtype][0]=obj["on"+evtype]).__EventID=0;//添加到预留的0位
//并且给原来的事件处理函数增加一个ID
}
obj["on"+evtype]=addEvent.execEventHandles;
//当事件发生时，execEventHandles遍历表obj.__EventHandles[evtype]并执行其中的函数
}
}
}
addEvent.__EventHandlesCounter=1;//计数器,0位预留它用
addEvent.execEventHandles = function (evt) {//遍历所有的事件处理函数并执行
if (!this.__EventHandles) {return true;}
evt = evt || window.event;
var fns = this.__EventHandles[evt.type];
for (var i in fns) {
fns[i].call(this);
}
};
/*
function delEvent(obj,evtype,fn,useCapture) {
if (obj.removeEventListener) {//先使用W3C的方法移除事件处理函数
obj.removeEventListener(evtype,fn,!!useCapture);
} else {
if (obj.__EventHandles) {
var fns = obj.__EventHandles[evtype];
if (fns) {delete fns[fn.__EventID];}
}
}
}
function fixEvent(evt) {//fixEvent函数不是单独执行的，它必须有一个事件对象参数，而且只有事件发生时它才被执行！最好的方法是把它整合到addEvent函数的execEventHandles里面
if (!evt.target) {
evt.target = evt.srcElement;
evt.preventDefault = fixEvent.preventDefault;
evt.stopPropagation = fixEvent.stopPropagation;
if (evt.type == "mouseover") {
evt.relatedTarget = evt.fromElement;
} else if (evt.type =="mouseout") {
evt.relatedTarget = evt.toElement;
}
evt.charCode = (evt.type=="keypress")?evt.keyCode:0;
evt.eventPhase = 2;//IE仅工作在冒泡阶段
evt.timeStamp = (new Date()).getTime();//仅将其设为当前时间
}
return evt;
}
fixEvent.preventDefault =function () {
this.returnValue = false;//这里的this指向了某个事件对象，而不是fixEvent
};
fixEvent.stopPropagation =function () {
this.cancelBubble = true;
};*/
//console.log(EventUtil.$("button3"));//返回EventUtil函数的对象属性
//EventUtil.$("button3").onclick= eventfun;//2.使用为对象事件属性赋值的方法来实现事件的监听
//EventUtil.$("button3").onclick= eventfun2;//为事件属性添加多个方法时，为后者
//EventUtil.$("button3").onclick= eventfun;//事件捕获是从事件对象逐层外父级检察一直到window对象
var EventUtil =function(){
function getByid(id){
return document.getElementById(id);
};
// written by Dean Edwards, 2005
// with input from Tino Zijdel, Matthias Miller, Diego Perini
// http://dean.edwards.name/weblog/2005/10/add-event/
function addEvent(element, type, handler) {
if (element.addEventListener) {
element.addEventListener(type, handler, false);
} else {
// assign each event handler a unique ID
if (!handler.$$guid) handler.$$guid = addEvent.guid++;
// create a hash table of event types for the element
if (!element.events) element.events = {};
// create a hash table of event handlers for each element/event pair
var handlers = element.events[type];
if (!handlers) {
handlers = element.events[type] = {};
// store the existing event handler (if there is one)
if (element["on" + type]) {
handlers[0] = element["on" + type];
}
}
// store the event handler in the hash table
handlers[handler.$$guid] = handler;
// assign a global event handler to do all the work
element["on" + type] = handleEvent;
}
};
// a counter used to create unique IDs
addEvent.guid = 1;
function removeEvent(element, type, handler) {
if (element.removeEventListener) {
element.removeEventListener(type, handler, false);
} else {
// delete the event handler from the hash table
if (element.events && element.events[type]) {
delete element.events[type][handler.$$guid];
}
}
};
function handleEvent(event) {
var returnValue = true;
// grab the event object (IE uses a global event object)
event = event || fixEvent(((this.ownerDocument || this.document || this).parentWindow || window).event);
// get a reference to the hash table of event handlers
var handlers = this.events[event.type];
// execute each event handler
for (var i in handlers) {
this.$$handleEvent = handlers[i];
if (this.$$handleEvent(event) === false) {
returnValue = false;
}
}
return returnValue;
};
function fixEvent(event) {
// add W3C standard event methods
event.preventDefault = fixEvent.preventDefault;
event.stopPropagation = fixEvent.stopPropagation;
return event;
};
fixEvent.preventDefault = function() {
this.returnValue = false;
};
fixEvent.stopPropagation = function() {
this.cancelBubble = true;
};
function tableAddEvent(){
};
return{
add:addEvent,
remove:removeEvent,
$:getByid
}
}();
var outEleObj = EventUtil.$("outEle");
//addEvent.apply(EventUtil,[outEleObj,"click",eventfun3]);
//EventUtil.add(outEleObj,"click",eventfun3);
var inputObj = EventUtil.$("button4");
var tableEle = EventUtil.$("htmlEleTable");
var tabTrEle = tableEle.getElementsByTagName("tr");
EventUtil.add(tableEle,"click",eventfun3);
for (i=0; i<tabTrEle.length; i++){
EventUtil.add(tabTrEle[i],"click",eventfun3);
}
EventUtil.remove(tableEle,"click",eventfun3);//事件冒删除方法
EventUtil.add(tableEle,"click",eventfun3);//事件冒泡添加方法
//EventUtil.add(inputObj,"click",eventfun3);
//EventUtil.remove(outEleObj,"click",eventfun3);
//console.log(addEvent);
//addEvent(inputObj,"click",eventfun3,true);
//delEvent(outEleObj,"click",eventfun3,false);
</script>
</body>
</html>
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