Bootstrap 4 个响应式菜单停止响应：-/

Question

作为一个非前端人员，我已经看了一些答案，所以不要扔烂番茄;-)

我有一个 bootstrap 4 导航菜单，应该是响应式的

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>Navigation Menu</title>

    <script src="Libs/JQuery/jquery-3.3.1.slim.min.js"></script>
    <script>window.jQuery || document.write('<script src="Libs/JQuery/jquery-3.3.1.slim.min.js"><\/script>')</script>
    <script src="Libs/Popper/popper.min.js"></script>
    <script src="Libs/Bootstrap/js/bootstrap.bundle.js"></script>



    <link rel="stylesheet" type="text/css" href="Libs/Bootstrap/css/bootstrap.css" media="all">
    <link rel="stylesheet" type="text/css" href="Libs/Bootstrap/css/bootstrap-grid.css" media="all">
    <link rel="stylesheet" type="text/css" href="Libs/Bootstrap/css/bootstrap-reboot.css" media="all">
    <!--
    <link rel="stylesheet" type="text/css" href="css/Common.css" media="all">
    <link rel="stylesheet" type="text/css" href="css/Slider.css" media="all">
    -->

</head>

<body>

<nav class="navbar navbar-nav navbar-expand-md navbar-light bg-light">

    <a class="navbar-brand" href="#"><img src="Images/logo.png" alt="Logo">
        <!-- Carousel -->
    </a>

    <div class="collapse navbar-collapse offcanvas-collapse" id="main_menu">

        <ul class="navbar-nav mr-auto">
            <li class="nav-item">
                <a class="nav-link" href="#">PRODUKTE</a>
            </li>
            <li class="nav-item">
                <a class="nav-link" href="#">DIENSTLEISTUNGEN</a>
            </li>
            <li class="nav-item">
                <a class="nav-link" href="#">UNTERNEHMEN</a>
            </li>
            <li class="nav-item">
                <a class="nav-link" href="#">NEWSROOM-STORY</a>
            </li>
            <li class="nav-item">
                <a class="nav-link" href="#">SPOTLIGHT:TECHNIK

                </a>
            </li>
        </ul>

        <ul class="navbar-nav mr-auto">
            <li class="nav-item">
                <a class="nav-link text-danger" href="#">KUNDEN-COCKPIT</a>
            </li>
            <li class="nav-item">
                <a class="nav-link text-danger" href="#">SHOP</a>
            </li>
            <li class="nav-item">
                <a class="nav-link" href="#">DATENSCHUTZ</a>
            </li>
            <li class="nav-item">
                <a class="nav-link" href="#">KONTAKT</a>
            </li>
        </ul>

        <!-- Language Menu -->
        <ul class="navbar-nav mr-auto">
            <li class="nav-item">
                <a class="nav-link" href="#">DE</a>
            </li>
            <li class="nav-item">
                <a class="nav-link" href="#">EN</a>
            </li>
        </ul>

        <button class="navbar-toggler p-0 border-0" type="button" data-toggle="offcanvas">
            <span class="navbar-toggler-icon"></span>
        </button>

    </div>

</nav>

菜单在停止工作之前似乎工作正常。我浏览了很多教程，也浏览了其他人的问题。

我尝试将 JQuery 和所有其他 JavaScript 文件移动到 CSS 之前加载。我已经尝试过其他查看其他站点上的布局并将他们的一些代码复制到我的代码中，但是当 window 大小发生变化时，事情仍然不想改变。

徽标保留，但菜单项要么保持原样，要么完全从屏幕上消失。

我的同事看了代码，他和我一样目瞪口呆，但我们都更专注于后端开发:-)

Answer 1

您包含了多个并非真正需要的 css 文件，如果您打算包含整个框架，则只需要 bootstrap.css 或 bootstrap.min.css，以及 jQuery 和 boostrap.js。尝试遵循文档中详述的结构：https://getbootstrap.com/docs/4.1/getting-started/introduction/

现在这是您拥有功能响应式导航栏所需的标记，将其与您的代码进行比较以查看是否缺少某些内容；我看到你包括多个 ul.navbar-nav 为什么？

编辑： 我想我在切换按钮上发现了你的问题：

<button class="navbar-toggler p-0 border-0 ml-auto" type="button" data-toggle="collapse" data-target="#main_menu">
     <span class="navbar-toggler-icon"></span>
<button>

把data-toggle改成collapse，不知道为什么要改；你还需要在同一个按钮上有一个 data-target="#your navbar ID"

<link href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" rel="stylesheet"/>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js"></script>
<nav class="navbar navbar-expand-lg navbar-light bg-light">
  <a class="navbar-brand" href="#">Navbar</a>
  <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
    <span class="navbar-toggler-icon"></span>
  </button>

  <div class="collapse navbar-collapse" id="navbarSupportedContent">
    <ul class="navbar-nav mr-auto">
      <li class="nav-item active">
        <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">Link</a>
      </li>
      <li class="nav-item dropdown">
        <a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
          Dropdown
        </a>
        <div class="dropdown-menu" aria-labelledby="navbarDropdown">
          <a class="dropdown-item" href="#">Action</a>
          <a class="dropdown-item" href="#">Another action</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="#">Something else here</a>
        </div>
      </li>
      <li class="nav-item">
        <a class="nav-link disabled" href="#">Disabled</a>
      </li>
    </ul>
    <form class="form-inline my-2 my-lg-0">
      <input class="form-control mr-sm-2" type="search" placeholder="Search" aria-label="Search">
      <button class="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button>
    </form>
  </div>
</nav>

这是在使用您的代码

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js"></script>
<link href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" rel="stylesheet" />
<nav class="navbar navbar-expand-lg navbar-light bg-light">

  <a class="navbar-brand" href="#"><img src="Images/logo.png" alt=""> Brand
  </a>

  <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#main_menu">
                                <span class="navbar-toggler-icon"></span>
                            </button>

  <div class="collapse navbar-collapse" id="main_menu">

    <ul class="navbar-nav mr-auto">
      <li class="nav-item">
        <a class="nav-link" href="#">PRODUKTE</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">DIENSTLEISTUNGEN</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">UNTERNEHMEN</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">NEWSROOM-STORY</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">SPOTLIGHT:TECHNIK
                        
                                        </a>
      </li>
    </ul>

    <ul class="navbar-nav mr-auto">
      <li class="nav-item">
        <a class="nav-link text-danger" href="#">KUNDEN-COCKPIT</a>
      </li>
      <li class="nav-item">
        <a class="nav-link text-danger" href="#">SHOP</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">DATENSCHUTZ</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">KONTAKT</a>
      </li>
    </ul>

    <!-- Language Menu -->
    <ul class="navbar-nav mr-auto">
      <li class="nav-item">
        <a class="nav-link" href="#">DE</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">EN</a>
      </li>
    </ul>



  </div>

</nav>

Bootstrap 4 个响应式菜单停止响应：-/

Bootstrap 4 responsive menu stoped being responsive :-/

navbar

bootstrap-4

responsive