事件对象
什么是事件对象?
在触发DOM上的事件时都会产生一个对象。
事件对象event
1.DOM中的事件对象
(1)\type属性用于获取事件类型
(2)\target属性用于获取事件目标
(3)\stopPropagation()方法用于阻止事件冒泡
(4)\preventDefault()方法用于阻止事件的默认行为
2.IE中的事件对象
(1)\type属性用于获取事件类型
(2)\srcElement属性 用于获取事件目标
(3)\cancelBubble属性 true阻止事件冒泡
(4)\returnValue属性 false阻止事件的默认行为
封装函数eventUtil():
var eventUtil = {
getEvent:function (event) {
return event?event:window.event;
},
getType: function (event) {
return event.type;
},
getTarget:function (event) {
return event.target||event.srcElement;
},
//阻止冒泡
stopPropagation:function (event) {
if(event.stopPropagation){
event.stopPropagation();
}else {
event.cancelBubble=true;
}
},
//阻止事件默认行为;
preventDefault:function(event){
if(event.preventDefault){
event.preventDefault();
}else {
event.returnValue = false;
}
},
//添加具柄;
addHandler: function (element, type, Handler) {
if (element.addEventListener) {
element.addEventListener(type, Handler, false);
} else if (element.attachEvent) {
element.attachEvent("on" + type, Handler);
} else {
element["on" + type] = Handler;
}
},
//删除具柄;
removeHandler: function (element, type, Handler) {
if (element.removeEventListener) {
element.removeEventListener(type, Handler, false);
} else if (element.detachEvent) {
element.detachEvent("on" + type, Handler);
} else {
element["on" + type] = null;
}
}
};
示例:
html:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="eventUtil.js"></script>
<script src="test1.js"></script>
</head>
<body>
<div id="div">
<input type="button" value="click1" id="btn1">
<a href="https://www.baidu.com" id="a">百度</a>
</div>
</body>
</html>
js:
window.onload = function () {
var btn1 = document.getElementById("btn1");
var a = document.getElementById("a");
var div = document.getElementById("div");
function show() {
alert("btn clicked");
}
eventUtil.addHandler(div,"click",function () {
alert("我是父盒子");
});
eventUtil.addHandler(btn1,"click",show);
eventUtil.addHandler(a,"click",function (e) {
e = eventUtil.getEvent(e);
alert(eventUtil.getTarget(e));
eventUtil.stopPropagation(e);
eventUtil.preventDefault(e);
});
eventUtil.removeHandler(btn1,"click",show);
};