Bootstrap的问题：小屏幕上的Navbar折叠移动不起作用

问题描述

我的引导导航栏有问题。我想将元素折叠成当前，导航栏在移动设备上看起来像这样，正如我所期望的那样：current state before clicking on the hamburger icon

单击“汉堡包”图标后，它变黑了。当前的代码是：

<head>
    <Meta charset="UTF-8">
    <Meta name="viewport" content="width=device-width,initial-scale=1,shrink-to-fit=no">
    <!-- Bootstrap CSS -->
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">
    <link rel="stylesheet" type="text/css" href="../css/index.css">
    <script src="https://code.jquery.com/jquery-3.5.1.js" integrity="sha256-QWo7LDvxbWT2tbbQ97B53yJnYU3WhH/C8ycbRAkjPDc=" crossorigin="anonymous"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" integrity="sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvcwpIPm49" crossorigin="anonymous"></script>
    <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" integrity="sha384-ChfqqxuZUCnjsK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" crossorigin="anonymous"></script>
    <!--my script-->
    <script src="../js/script.js"></script>
    <title>Katholische Jugend Maudach</title>
</head>
<body>
<div class="container">
<nav class="navbar navbar-expand-lg navbar-light bg-light sticky-top" role="navigation">
            <a class="navbar-brand" href="../index.html">
                <img src="../images/logo.png" height="60px" width="60px" />
            </a>
            <button class="navbar-toggler" type="button" data-toggle="collapse"
                    data-target="#navbarContent" aria-controls="navbarContent" aria-expanded="false" aria-label="Toggle navigation">
                <span class="navbar-toggler-icon"></span>
            </button>

        <div class="collapse navbar-collapse" id="navbarContent">
        <ul class="navbar-nav mr-auto">
                      <li class="nav-item active">
                            <a class="nav-link" href="activities.html">Topic 2</a>
                     </li>
            <li class="nav-item">
                <a class="nav-link" href="downloads.html">Topic 1</a>
            </li>
            <li class="nav-item">
                <a class="nav-link" href="about.html">Topic 3</a>
            </li>
            <li class="nav-item">
                <a class="nav-link" href="quiz.html">Topic 4</a>
            </li>
            <li class="nav-item">
                <a class="nav-link" href="impressum.html">Topic 5</a>
            </li>
            <li class="nav-item ">
                <button class="btn btn-success" onclick="sendMail()">Contakt</button>
            </li>
        </ul>
        </div>

</nav>
</div>
</body>

单击汉堡包图标后，将发生以下情况。它只是变黑了，只显示了按钮。

after clicking the hamburger icon

除代码外，还有一些其他信息：

我在CORS上遇到了问题，并在各处添加了CORS。
当前代码未部署在服务器上。只是在浏览器中显示的HTML文件
使用 jquery 将导航栏动态加载onload 到网页中（如果导航栏发生变化，我只需要更改一个文件）

如果我需要提供更多信息，请告诉我。

感谢任何提示，感谢您的宝贵时间。

解决方法

理想情况下，您应该将脚本CDN放在正文的末尾，也应按特定顺序放置。像这样：

. . .
<script src="https://code.jquery.com/jquery-3.5.1.js" integrity="sha256-QWo7LDvxbWT2tbbQ97B53yJnYU3WhH/C8ycbRAkjPDc=" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" integrity="sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" integrity="sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" crossorigin="anonymous"></script>
</body>

我不确定这是否有帮助。尝试一次。

代码正在运行，问题出在我的自定义CSS样式表中。

html javascript twitter-bootstrap