這是程式碼：
<nav xmlns:sec="http://www.thymeleaf.org/extras/spring-security" class="navbar navbar-expand-lg fixed-top container-fluid" id="navbar">
<div class="container px-4">
<a class="navbar-brand" href="/main"> <img src="https://i.imgur.com/BKHVvT0.png" style="width: 100px; height: auto;"> </a>
<button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarResponsive" aria-controls="navbarResponsive" aria-expanded="false" aria-label="Toggle navigation"><span class="navbar-toggler-icon"></span></button>
<div class="collapse navbar-collapse" id="navbarResponsive">
<ul class="navbar-nav ms-auto">
<li sec:authorize="isAnonymous()" class="nav-item"><a class="nav-link" href="/login">Inicio sesión</a></li>
<li sec:authorize="isAnonymous()" class="nav-item"><a class="nav-link" href="/register">Registro Cliente</a></li>
<li sec:authorize="isAnonymous()" class="nav-item"><a class="nav-link" href="/registrohotel">Registro Hotel</a></li>
<li sec:authorize="hasAuthority('CLIENTE')" class="nav-item"><a class="nav-link" href="/historialReservaClienteVigentes">Tus reservas</a></li>
<li sec:authorize="hasAuthority('CLIENTE')" class="nav-item"><a class="nav-link" href="/perfilcliente">Perfil</a></li>
<li sec:authorize="hasAuthority('CLIENTE')" class="nav-item"><a sec:authorize="isAuthenticated()" class="nav-link" th:href="@{/logout}"> <i class=" fas fa-door-open"></i></a></li>
<li sec:authorize="hasAuthority('HOTEL')" class="nav-item"><a class="nav-link" href="/admin">Administrador</a></li>
<li sec:authorize="hasAuthority('HOTEL')" class="nav-item"><a class="nav-link" href="/perfilhotel">Perfil</a></li>
<li sec:authorize="hasAuthority('HOTEL')" class="nav-item"><a sec:authorize="isAuthenticated()" class="nav-link" th:href="@{/logout}"> <i class=" fas fa-door-open"></i></a></li>
</ul>
</div>
</div>
事實是它確實出現在螢幕上，但是在互動時它什麼都不做。切換器底部確實出現，但單擊時，它不會使導航項目出現在其上。
如果你加入 bootstrap cdns: 腳本和 css，它就會起作用。請參閱下面的程式碼片段：