设置引导按钮的活动状态
要设置引导按钮的活动状态，请使用.active类。
该按钮将显示为按下状态，如以下代码所示
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>
<p>The following are some buttons:</p>
<button type = "button" class = "btn btn-default btn-lg ">
Default Button
</button>
<button type = "button" class = "btn btn-default btn-lg active">
Active Button
</button>
</body>
</html>