7.17 this的应用1
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
.laoLiu{
width:300px ; height:100px; line-height:30px; text-align:center ;
background:burlywood;float:left;
color:blue;font-size:24px;margin-left:10px;margin-top:20px;
}
</style>
<script type="text/javascript">
window.onload=function(){
var z=document.getElementsByClassName("laoLiu")
for (var i=0; i<z.length;i++){
z[i].onclick=function(){
//this指向正在操作的元素
this.innerText=Math.random();
};
};
};
</script>
</head>
<body>
<div class="laoLiu" ></div>
<div class="laoLiu" ></div>
<div class="laoLiu" ></div>
<div class="laoLiu" ></div>
</body>
</html>
点击后返回值：