时间戳

首页 > 解决方案 > 引导导航栏下拉菜单/折叠的导航栏未打开

javascript - 引导导航栏下拉菜单/折叠的导航栏未打开

问题描述

我正在尝试向该网站添加一个导航栏，但由于某种原因，它并没有像我想象的那样运行。我要解决的主要问题是让下拉菜单实际显示列表。它在视觉上看起来菜单已经展开，但我不知道这是否与它为什么不起作用有关。目前，折叠的版本只能从汉堡菜单中打开，因为我添加了 CSS。如果没有 CSS，导航栏会展开，但会立即再次折叠。我尝试过的事情：

我很感激有人可以帮助我弄清楚为什么这不起作用。谢谢！

.navbar-collapse.collapse.in {
  display: block!important;
}
<!DOCTYPE html>
<html>
<head>
   <title>Title</title>


  <script
  src="https://code.jquery.com/jquery-3.2.1.min.js">
  </script>
  <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
  <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css">
  
  <link rel="stylesheet" href="index.css">

   

</head>
<body>

<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">
          Products
        </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" href="#">About Us</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>

<div class="jumbotron">
  <h1 class="display-3">Hello, world!</h1>
  <p class="lead">This is a simple hero unit, a simple jumbotron-style component for calling extra attention to featured content or information.</p>
  <hr class="my-4">
  <p>It uses utility classes for typography and spacing to space content out within the larger container.</p>
  <p class="lead">
    <a class="btn btn-primary btn-lg" href="#" role="button">Learn more</a>
  </p>
</div>

</body>
</html>

标签： javascripthtmlcsstwitter-bootstrapnavbar

解决方案

那是因为您bootstrap.js的版本是 3.3.7，这不是您实现子菜单的方式（在引导程序 3 上）。虽然，如果您已经在使用 bootstrap 4，您应该考虑将您的版本更新到 4.0.0 版（并且您应该使用和bootstrap.js的相同版本以避免意外错误（就像您刚刚遇到的那样）。bootstrap.jsbootstrap.css

.navbar-collapse.collapse.in {
  display: block!important;
}
<!DOCTYPE html>
<html>
<head>
   <title>Title</title>


  <script
  src="https://code.jquery.com/jquery-3.2.1.min.js">
  </script>
  <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js"></script>
  <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css">
  
  <link rel="stylesheet" href="index.css">

   

</head>
<body>

<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">
          Products
        </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" href="#">About Us</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>

<div class="jumbotron">
  <h1 class="display-3">Hello, world!</h1>
  <p class="lead">This is a simple hero unit, a simple jumbotron-style component for calling extra attention to featured content or information.</p>
  <hr class="my-4">
  <p>It uses utility classes for typography and spacing to space content out within the larger container.</p>
  <p class="lead">
    <a class="btn btn-primary btn-lg" href="#" role="button">Learn more</a>
  </p>
</div>

</body>
</html>

推荐阅读