Bootstrap4 Dropdown Menu Using HTML CSS

<div class="container-fluid">
       <div class="dropdown mt-3">
           <button class="btn btn-primary dropdown-toggle" type="button" id="dropdownMenuButton" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
             Dropdown button
           </button>
           <div class="dropdown-menu" aria-labelledby="dropdownMenuButton">
             <a class="dropdown-item" href="#">Action</a>
             <a class="dropdown-item" href="#">Another action</a>
             <a class="dropdown-item" href="#">Something else here</a>
           </div>
         </div>
   </div>

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css"  >

<script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" ></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" ></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js" ></script>