<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<link rel="stylesheet" href="./css/bootstrap.css">
</head>
<body>
<div class="dropdown open">
<button class="btn btn-default" data-toggle="dropdown">
选择今天要开的车 <span class="caret"></span>
</button>
<ul class="dropdown-menu">
<li><a href="#">宝马</a></li>
<li><a href="#">奔驰</a></li>
<li><a href="#">auto</a></li>
<li><a href="#">mini</a></li>
</ul>
</div>
<script src="./js/jquery-1.12.4.js"></script>
<script>
$('.btn,.btn-default').click(function() {
$('.dropdown').toggleClass('open')
})
$('.dropdown-menu li').click(function() {
$(this).addClass('active').siblings().removeClass('active');
$('button').html($(this).children('a').text())
})
</script>
</body>
</html>