1.运行效果如图所示
2.实现代码如下
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<title>表单控件——块状按</title>
<!-- 最新版本的 Bootstrap 核心 CSS 文件 -->
<link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css"
integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh5u"
crossorigin="anonymous">
<!-- 可选的 Bootstrap 主题文件（一般不用引入） -->
<link rel="stylesheet"
href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap-theme.min.css"
integrity="sha384-rHyoN1iRsVXV4nD0JutlnGaslCJuC7uwjduW9SVrLvRYooPp2bWYgmgJQIXwl/Sp"
crossorigin="anonymous">
</head>
<body>
<form role="form">
<button class="btn btn-primary btn-lg btn-block" type="button">大型按钮.btn-lg</button>
<button class="btn btn-primary btn-block" type="button">正常按钮</button>
<button class="btn btn-primary btn-sm btn-block" type="button">小型按钮.btn-sm</button>
<button class="btn btn-primary btn-xs btn-block" type="button">超小型按钮.btn-xs</button>
</form>
<script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.min.js"></script>
<!-- 最新的 Bootstrap 核心 JavaScript 文件 -->
<script src="https://cdn.bootcss.com/bootstrap/3.3.7/js/bootstrap.min.js"
integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa"
crossorigin="anonymous"></script>
</body>
</html>
