Bootstrap 导航栏布局错误答案

【问题标题】：Error on Bootstrap navbar layoutBootstrap 导航栏布局错误
【发布时间】：2018-05-11 07:08:13
【问题描述】：

我的导航栏应该看起来像顶部的那个，但相反，它会在它的正下方输出混乱：

我该如何解决？

这是我的 html 文件中的代码：

   <nav class="navbar navbar-expand-lg navbar-dark 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>
    <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>
 </div>
</nav>

【问题讨论】：

添加一些代码和 jsfiddle 会有所帮助。
我是初学者，所以“添加一些代码”对我来说很模糊。这个场合有什么明显的例子吗？谢谢
添加一些代码意味着编辑您的帖子并输入您拥有的代码

标签： html css twitter-bootstrap navbar

【解决方案1】：

您的代码被分离和损坏，对于主导航栏类，它应该是

navbar-light bg-light

不是

navbar-dark bg-light

请阅读documentation 了解如何使用 Bootstrap。

工作导航栏示例：

<link href="https://maxcdn.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css" rel="stylesheet"/>

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.1.0/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>
        <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>
  </div>
</nav>

【讨论】：