Why don't the drop-down menu items show up?

Question

My navigation bar uses Bootstrap 5. The problem is that the dropdown item for the user icon (login) is not showing up. This is my code:

<button class="btn dropdown-toggle" type="button" id="userDropdown" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
                <i class="fa-solid fa-user text-white fs-5"></i>
            </button>
            <div class="dropdown-menu dropdown-menu-right" aria-labelledby="userDropdown">
                <a class="dropdown-item" href="#">Login</a>
            </div>

Answer 1

For Boostrap 5, you need data-bs-toggle="dropdown" instead of data-toggle:

<link href="https://cdn.jsdelivr.net/npm/bootstrap@5.1.3/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-1BmE4kWBq78iYhFldvKuhfTAU6auU8tT94WrHftjDbrCEXSU1oBoqyl2QvZ6jIW3" crossorigin="anonymous">
<script src="https://cdn.jsdelivr.net/npm/bootstrap@5.1.3/dist/js/bootstrap.bundle.min.js" crossorigin="anonymous"></script>
    
<button class="btn dropdown-toggle" type="button" id="userDropdown" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
    <i class="fa-solid fa-user text-white fs-5"></i>
</button>            
            
<div class="dropdown-menu dropdown-menu-right" aria-labelledby="userDropdown">
    <a class="dropdown-item" href="#">Login</a>
</div>