如何使用Creative Tim的Material Dashboard在顶部导航栏中显示下拉菜单

<nav class="navbar navbar-expand-lg navbar-transparent navbar-absolute fixed-top">
  <div class="container-fluid">
    <div class="navbar-wrapper">
      <a class="navbar-brand" href="#">Your Brand</a>
    </div>
    <<button class="navbar-toggler" type="button" data-toggle="collapse" aria-controls="navigation-index" aria-expanded="false" aria-label="Toggle navigation">
      <span class="sr-only">Toggle navigation</span>
      <span class="navbar-toggler-icon icon-bar"></span>
      <span class="navbar-toggler-icon icon-bar"></span>
      <span class="navbar-toggler-icon icon-bar"></span>
    </button>
    <div class="collapse navbar-collapse justify-content-end">
      <ul class="navbar-nav">
        <li class="nav-item dropdown">
          <a class="nav-link" href="#" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
            Dropdown <i class="material-icons">keyboard_arrow_down</i>
          </a>
          <div class="dropdown-menu dropdown-menu-right" aria-labelledby="navbarDropdownMenuLink">
            <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>
        </li>
      </ul>
    </div>
  </div>
</nav>

$(document).ready(function() {
  // 初始化导航栏
  md.initDashboardPageCharts();
});