<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css"> <script src="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.min.js"></script> <script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script> <!------ Include the above in your HEAD tag ----------> <div class="container"> <div class="row"> <h2>Create your snippet's HTML, CSS and Javascript in the editor tabs</h2> </div> <div class="dropdown-menu"> <h6 class="dropdown-header">Dropdown header</h6> <a class="dropdown-item" href="#">Action</a> <a class="dropdown-item" href="#">Another action</a> </div> </div