要将响应功能添加到导航栏，需要折叠的内容需要使用类.collapse，.navbar-collapse包裹在<div>中。
您可以尝试运行以下代码来
<!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 style="background: #F5CBA7;"> <nav class = "navbar navbar-default" role = "navigation"> <div class = "navbar-header"> <button type = "button" class = "navbar-toggle" data-toggle = "collapse" data-target = "#example-navbar-collapse"> <span class = "sr-only">Toggle navigation</span> <span class = "icon-bar"></span> <span class = "icon-bar"></span> <span class = "icon-bar"></span> </button> <a class = "navbar-brand" href = "#">Tools</a> </div> <div class = "collapse navbar-collapse" id = "example-navbar-collapse"> <ul class = "nav navbar-nav"> <li class = "active"><a href = "#">Online Compiler</a></li> <li><a href = "#">Image Editor</a></li> <li class = "dropdown"> <a href = "#" class = "dropdown-toggle" data-toggle = "dropdown"> Whiteboard <b class = "caret"></b> </a> <ul class = "dropdown-menu"> <li><a href = "#">Image Optimizer</a></li> </ul> </li> </ul> </div> </nav> </body> </html>