Bootstrap .btn-sm类
要在Bootstrap中创建一个小按钮，请使用.btn-sm类。
您可以尝试运行以下代码来实现btn-sm类
示例
<!DOCTYPE html>
<html>
<head>
<title>Bootstrap Example</title>
<meta name = "viewport" content = "width=device-width, initial-scale = 1">
<link rel = "stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css">
<script src = "https://cdn.staticfile.org/jquery/3.3.1/jquery.min.js"></script>
<script src = "https://stackpath.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.min.js"></script>
</head>
<body>
<button type = "button" class = "btn btn-default btn-sm">
Small button
</button>
<button type = "button" class = "btn btn-default btn-sm">
Result
</button>
</body>
</html>