源代码：
左右布局
点击运行
<!DOCTYPE html> <html> <head> <title>Bootstrap 实例</title> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1"> <link rel="stylesheet" href="https://cdn.staticfile.org/twitter-bootstrap/4.3.1/css/bootstrap.min.css"> <script src="https://cdn.staticfile.org/jquery/3.2.1/jquery.min.js"></script> <script src="https://cdn.staticfile.org/popper.js/1.15.0/umd/popper.min.js"></script> <script src="https://cdn.staticfile.org/twitter-bootstrap/4.3.1/js/bootstrap.min.js"></script> </head> <body> <nav class="navbar navbar-expand-sm bg-dark navbar-dark"> <!-- Brand --> <a class="navbar-brand" href="#">Logo</a> <!-- Links --> <ul class="navbar-nav"> <li class="nav-item"> <a class="nav-link" href="#">Link 1</a> </li> <li class="nav-item"> <a class="nav-link" href="#">Link 2</a> </li> <!-- Dropdown --> <li class="nav-item dropdown"> <a class="nav-link dropdown-toggle" href="#" id="navbardrop" data-toggle="dropdown"> Dropdown link </a> <div class="dropdown-menu"> <a class="dropdown-item" href="#">Link 1</a> <a class="dropdown-item" href="#">Link 2</a> <a class="dropdown-item" href="#">Link 3</a> </div> </li> </ul> </nav> <br> <div class="container"> <h3>导航栏使用下拉菜单</h3> <p>导航栏上可以设置下拉菜单。</p> </div> </body> </html>
运行结果