<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<script src="https://code.jquery.com/jquery-2.2.4.min.js" integrity="sha256-BbhdlvQf/xTY9gja0Dq3HiwQF8LaCRTXxZKRutelT44="
crossorigin="anonymous"></script>
</head>
<body>
<div class="a">
<div class="b">12345</div>
<div class="c">
<div class="d">sub12345</div>
<div class="d">sub12345</div>
<div class="d">sub12345</div>
<div class="d">sub12345</div>
</div>
</div>
<div class="a">
<div class="b">12345</div>
<div class="c">
<div class="d">sub12345</div>
<div class="d">sub12345</div>
<div class="d">sub12345</div>
<div class="d">sub12345</div>
</div>
</div>
<div class="a">
<div class="b">12345</div>
<div class="c">
<div class="d">sub12345</div>
<div class="d">sub12345</div>
<div class="d">sub12345</div>
<div class="d">sub12345</div>
</div>
</div>
</body>
<script>
$(".a").on('click',function(){
$(".c").removeClass("on");
$(this).children('.c').addClass("on");
})
</script>
<style>
.a {
border-bottom: 1px solid #efefef;
}
.b{ height: 40px;line-height: 40px; }
.d{ height:35px; background: rgba(0, 0, 0, 0.1);line-height: 35px; text-indent: 20px;}
.b,.d { cursor: pointer; padding-left: 20px;}
.b:hover,.d:hover{ background: #fff;}
/* 隱藏顯示方式一 */
.c {
height: 0;
overflow: hidden;
transition: all .5s ease;
}
.c.on{ height: 100px; overflow-x: auto; transition: all .5s ease;}
/* 隱藏顯示方式二 */
/* .c {display: none;}
.c.on{ display: block;} */
</style>
</html>
