<!DOCTYPE html>
<html lang="en">
<head>
<title>Bootstrap Example</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://apps.bdimg.com/libs/bootstrap/3.3.0/css/bootstrap.min.css">
<script src="https://libs.baidu.com/jquery/2.1.4/jquery.min.js"></script>
<script src="https://apps.bdimg.com/libs/bootstrap/3.3.0/js/bootstrap.min.js"></script>
</head>
<body>
<div class="container">
<h2>Form control: select</h2>
<p>The form below contains two dropdown menus (select lists):</p>
<form>
<div class="form-group">
<label for="sel1">Select list (select one):</label>
<select class="form-control" id="sel1">
<option>1
<option>2
<option>3
<option>4
</select>
<br>
<label for="sel2">Mutiple select list (hold shift to select more than one):</label>
<select multiple="" class="form-control" id="sel2">
<option>1
<option>2
<option>3
<option>4
<option>5
</select>
</div>
</form>
</div>
</body>
</html>