nav bar drop down

<li class="nav-item dropdown"> <a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false"> Dropdown </a> <div class="dropdown-menu" aria-labelledby="navbarDropdown"> <a class="dropdown-item" href="#">Action</a> <a class="dropdown-item" href="#">Another action</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="#">Something else here</a> </div> </li>