<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 ----------> <link href="//netdna.bootstrapcdn.com/bootstrap/3.0.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css"> <script src="//netdna.bootstrapcdn.com/bootstrap/3.0.0/js/bootstrap.min.js"></script> <script src="//code.jquery.com/jquery-1.11.1.min.js"></script> <!------ Include the above in your HEAD tag ----------> <div class="container"> <div class="row"> <div class="dropdown"> <a id="dLabel" role="button" data-toggle="dropdown" class="btn btn-primary" data-target="#" href="/page.html"> Products <span class="caret"></span> </a> <ul class="dropdown-menu multi-level" role="menu" aria-labelledby="dropdownMenu"> <li class="dropdown-submenu"> <a tabindex="-1" href="#">Printers & All in one</a> <ul class="dropdown-menu"> <li><a tabindex="-1" href="#">For Homeoffice/SmallOffice</a></li> </ul> </li> </ul> </div> </div> </div>