bootstrap下拉菜单不起作用

<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/css/bootstrap.min.css">
<script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/js/bootstrap.min.js"></script>

<div class="dropdown">
  <button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenuButton" data-bs-toggle="dropdown" aria-expanded="false">
    下拉菜单
  </button>
  <ul class="dropdown-menu" aria-labelledby="dropdownMenuButton">
    <li><a class="dropdown-item" href="#">菜单项1</a></li>
    <li><a class="dropdown-item" href="#">菜单项2</a></li>
    <li><a class="dropdown-item" href="#">菜单项3</a></li>
  </ul>
</div>

<script>
  document.addEventListener("DOMContentLoaded", function() {
    var dropdownToggleList = [].slice.call(document.querySelectorAll('.dropdown-toggle'))
    dropdownToggleList.map(function (dropdownToggle) {
      return new bootstrap.Dropdown(dropdownToggle)
    })
  });
</script>