创建一个红色按钮，指示在Bootstrap中存在危险
要在Bootstrap中创建一个指示危险的按钮，请使用.btn-danger类。
您可以尝试运行以下代码来实现。btn-危险等级-
示例
<!DOCTYPE html>
<html>
<head>
<title>Bootstrap Example</title>
<link rel = "stylesheet" href="https://maxcdn.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://maxcdn.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.min.js"></script>
</head>
<body>
<p>Cick the below button in case of issues:</p>
<div class = "container">
<button type = "button" class="btn btn-danger">Danger</button>
</div>
</body>
</html>