btn-xs Bootstrap类的用法
使用btn-xsBootstrap类创建一个额外的小按钮。您可以尝试运行以下代码来实现btn-xs类：
示例
<!DOCTYPE html>
<html>
<head>
<title>Bootstrap Example</title>
<link href = "/bootstrap/css/bootstrap.min.css" rel = "stylesheet">
<script src = "/scripts/jquery.min.js"></script>
<script src = "/bootstrap/js/bootstrap.min.js"></script>
</head>
<body>
<div class = "btn-group">
<button type = "button" class = "btn btn-default dropdown-toggle btn-xs" data-toggle = "dropdown">
Subject
<span class = "caret"></span>
</button>
<ul class = "dropdown-menu" role = "menu">
<li><a href = "#">Programming</a></li>
<li><a href = "#">Web Dev</a></li>
<li><a href = "#">Database</a></li>
<li><a href = "#">Networking</a></li>
</ul>
</div>
</body>
</html>