Bootstrap 导航栏技术教程

Bootstrap 导航栏 技术教程

本文是一篇关于Bootstrap导航栏的详细技术教程，通过案例讲解如何创建和自定义导航栏。

一、引言

导航栏是网页中非常重要的组件，用于提供导航链接和页面标识。Bootstrap 提供了一个强大的导航栏组件，可以方便地创建响应式和美观的导航栏。

二、创建基本导航栏

首先，我们需要引入Bootstrap的CSS文件。在HTML文件的部分添加以下链接：

<link href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css" rel="external nofollow"  rel="stylesheet">

然后，我们可以使用以下HTML代码创建一个基本的导航栏：

<nav class="navbar navbar-expand-lg navbar-light bg-light">
  <a class="navbar-brand" href="#" rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow" >Navbar</a>
  <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNav" aria-controls="navbarNav" aria-expanded="false" aria-label="Toggle navigation">
    <span class="navbar-toggler-icon"></span>
  </button>
  <div class="collapse navbar-collapse" id="navbarNav">
    <ul class="navbar-nav">
      <li class="nav-item">
        <a class="nav-link" href="#" rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow" >Home <span class="sr-only">(current)</span></a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#" rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow" >Features</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#" rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow" >Pricing</a>
      </li>
      <li class="nav-item">
        <a class="nav-link disabled" href="#" rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  tabindex="-1" aria-disabled="true">Disabled</a>
      </li>
    </ul>
  </div>
</nav>

三、自定义导航栏

我们可以进一步自定义导航栏，例如更改颜色、添加下拉菜单等。

3.1 更改颜色

通过修改导航栏的类名，我们可以更改其颜色。例如，将bg-light更改为bg-dark，并将navbar-light更改为navbar-dark：

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

3.2 添加下拉菜单

我们可以在导航栏中添加下拉菜单，以便在点击时显示更多选项：

<li class="nav-item dropdown">
  <a class="nav-link dropdown-toggle" href="#" rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  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="#" rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow" >Action</a>
    <a class="dropdown-item" href="#" rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow" >Another action</a>
    <div class="dropdown-divider"></div>
    <a class="dropdown-item" href="#" rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow"  rel="external nofollow" >Something else here</a>
  </div>
</li>