<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title></title>
</head>
<link rel="stylesheet" type="text/css" href="css/common.css"/>
<style>
li{
border: 1px solid black;
width: 50px;
height: 50px;
display: inline-block;
text-align: center;
line-height: 50px;
}
.red{
border: 1px solid red;
}
</style>
<script src="./js/jquery-3.4.1.min.js" type="text/javascript"></script>
<script type="text/javascript">
$(function(){
$("#li1").click(function(){
$("img").attr("src","img/cake_03.jpg")
$(this).addClass("red").siblings().removeClass("red");
})
$("#li2").click(function(){
$("img").attr("src","img/cake_05.jpg")
$(this).addClass("red").siblings().removeClass("red");
})
$("#li3").click(function(){
$("img").attr("src","img/cake_07.jpg")
$(this).addClass("red").siblings().removeClass("red");
})
});
</script>
<body>
<ul>
<li id="li1" class="red">li1</li>
<li id="li2" >li2</li>
<li id="li3" >li3</li>
</ul>
<div>
<img src="img/cake_03.jpg" />
</div>
</body>
</html>
