<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
li {
width: 100px;
height: 100px;
background-image: url(images/1.jpg);
float: left;
margin-left: 20px;
list-style-type: none;
}
li.bg {
background-image: url(images/2.jpg);
}
</style>
</head>
<body>
<ul>
<li></li>
<li></li>
<li></li>
</ul>
<script>
window.onload = function(){
var myLi = document.querySelectorAll("li")
for (let i = 0; i < myLi.length; i++) {
myLi[i].onclick = function(){
// 清空所有的li上面的class
for (let j = 0; j < myLi.length; j++) {
myLi[j].className = "";
}
// 当前点击的这个li添加class
this.className = "bg"
}
}
}
</script>
</body>
</html>
