btn-group-vertical类使一组按钮显示为垂直堆叠而不是水平堆叠。
您可以尝试运行以下代码来实现btn-group-vertical类：
<!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> <div class = "btn-group-vertical"> <button type = "button" class = "btn btn-default">BCA</button> <button type = "button" class = "btn btn-default">B.Tech</button> <div class = "btn-group-vertical"> <button type = "button" class = "btn btn-default dropdown-toggle" data-toggle = "dropdown"> Masters <span class = "caret"></span> </button> <ul class = "dropdown-menu"> <li><a href = "#">MCA</a></li> <li><a href = "#">MBA</a></li> <li><a href = "#">M.Tech</a></li> <li><a href = "#">M.COM</a></li> </ul> </div> </div> </body></html>