.btn-warning类用于设置警告按钮。
您可以尝试运行以下代码来实现btn-warning类-
<!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-warning">Warning Button</button> </body> </html>