<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<script src="https://code.jquery.com/jquery-3.1.1.min.js"></script>
<title>Document</title>
</head>
<style>
.box{
width: 1200px;
margin: 0 auto;
}
.box_content{
width:100%;
list-style: none;
display: flex;
justify-content: space-between;
}
.box_content li{
width: 155px;
height: 410px;
margin-right: 15px;
background: #000;
transition: all 0.5s;
}
.box_content li:nth-last-child(1){
margin-right: 0;
}
.box_select{
flex-grow: 1;
transition-timing-function: ease;
-webkit-box-flex: 1;/* 兼容处理 */
}
</style>
<body>
<div class="box">
<ul class="box_content">
<li class="box_select">这是第1板块</li>
<li>这是第2板块</li>
<li>这是第3板块</li>
<li>这是第4板块</li>
<li>这是第5板块</li>
</ul>
</div>
</body>
<script>
$(function(){
$('.box_content>li').mouseenter(function(){
$(this).addClass('box_select').siblings().removeClass('box_select');
})
})
</script>
</html>
