JavaScript鼠标事件详解：DOM3定义的9种类型与触发机制

<body>
<input id="btn" type="button" value="click"/>
<script>
 var btn=document.getElementById("btn");
 btn.addEventListener("mousedown",function(event){
 console.log("mousedown");
 },false);
 btn.addEventListener("mouseup",function(){
 console.log("mouseup");
 },false);
 btn.addEventListener("click", function () {
 console.log("click");
 },false);
 btn.addEventListener("dblclick", function () {
 console.log("dblclick");
 },false);
</script>
</body>

<!DOCTYPE html>
<html>
<head lang="en">
 <meta charset="UTF-8">
 <title></title>
 <style>
 #outer{
  position: absolute;
  width: 200px;
  height: 200px;
  top:0;
  left: 0;
  bottom:0;
  right: 0;
  margin: auto;
  background-color: pink;
 }
 #inner{
  position: absolute;
  width: 100px;
  height:100px;
  top:50%;
  left:50%;
  margin-left: -50px;
  margin-top: -50px;;
  background-color: orange;
  text-align: center;
  line-height: 100px;
 }
 #outer,#inner{
  border-radius:50%;
 }
 </style>
 <script src="jquery-2.1.1.min.js"></script>
</head>
<body>
<body>
<div id="outer">
 <div id="inner">
 </div>
</div>
</body>
<script>
var parentDiv=document.getElementById("outer");
parentDiv.addEventListener("mouseover", function () {
 console.log("父div的mouseover事件被触发");
},false);
//parentDiv.addEventListener("mouseenter", function () {
// console.log("父div的mouseenter事件被触发");
//},false);
//parentDiv.addEventListener("mouseout", function () {
// console.log("父div的mouseout事件被触发");
//},false);
//parentDiv.addEventListener("mouseleave", function () {
// console.log("父div的mouseleave事件被触发");
//},false);
</script>
</body>
</html>

<script type="text/javascript">
document.onmousedown=function (ev)
{
 var oEvent=ev||event;
 alert(oEvent.button);// IE下鼠标的 左键是1 ， 右键是2 ff和chrome下 鼠标左键是0 右键是2
};
</script>