Bootstrap4 导航栏

导航栏是一个将商标、导航以及别的元素简单放置到一个简洁导航页头的的集合。在Bootstrap4中，导航栏的创建并不难，而且，可以使用各种类对其进行扩展。

基础导航栏创建

我们可以使用 .navbar 类来创建一个标准的导航栏，后面紧跟: .navbar-expand-xl|lg|md|sm 类来创建响应式的导航栏 (大屏幕水平铺开，小屏幕垂直堆叠)。

导航栏上的选项可以使用 <ul> 元素并添加 class="navbar-nav" 类。然后在 <li> 元素上添加 .nav-item 类， <a> 元素上使用 .nav-link 类:

实例：

<!DOCTYPE html>
<html>
<head>
  <title>Bootstrap4 实例</title>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/4.1.0/css/bootstrap.min.css">
  <script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.min.js"></script>
  <script src="https://cdn.bootcss.com/popper.js/1.12.5/umd/popper.min.js"></script>
  <script src="https://cdn.bootcss.com/bootstrap/4.1.0/js/bootstrap.min.js"></script>
</head>
<body>
<nav class="navbar navbar-expand-sm bg-light">
  <ul class="navbar-nav">
    <li class="nav-item">
      <a class="nav-link" href="#">Link 1</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#">Link 2</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#">Link 3</a>
    </li>
  </ul>
</nav>
</body>
</html>

垂直导航栏

通过删除 .navbar-expand-xl|lg|md|sm 类来创建垂直导航栏:

实例：

<!DOCTYPE html>
<html>
<head>
  <title>Bootstrap4 实例</title>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/4.1.0/css/bootstrap.min.css">
  <script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.min.js"></script>
  <script src="https://cdn.bootcss.com/popper.js/1.12.5/umd/popper.min.js"></script>
  <script src="https://cdn.bootcss.com/bootstrap/4.1.0/js/bootstrap.min.js"></script>
</head>
<body>
<nav class="navbar bg-light">
  <ul class="navbar-nav">
    <li class="nav-item">
      <a class="nav-link" href="#">Link 1</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#">Link 2</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#">Link 3</a>
    </li>
  </ul>
</nav>
</body>
</html>

不同颜色导航栏

可以使用以下类来创建不同颜色导航栏：.bg-primary, .bg-success, .bg-info, .bg-warning, .bg-danger, .bg-secondary, .bg-dark 和 .bg-light。

提示: 对于暗色背景需要设置文本颜色为浅色的，对于浅色背景需要设置文本颜色为深色的。

实例：

<!DOCTYPE html>
<html>
<head>
  <title>Bootstrap4 实例</title>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/4.1.0/css/bootstrap.min.css">
  <script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.min.js"></script>
  <script src="https://cdn.bootcss.com/popper.js/1.12.5/umd/popper.min.js"></script>
  <script src="https://cdn.bootcss.com/bootstrap/4.1.0/js/bootstrap.min.js"></script>
</head>
<body>
<div class="container">
  <h3>不同颜色导航栏</h3>
  <p>对于暗色背景需要设置文本颜色为浅色的，对于浅色背景需要设置文本颜色为深色的。</p>
</div>
<nav class="navbar navbar-expand-sm bg-light navbar-light">
  <ul class="navbar-nav">
    <li class="nav-item active">
      <a class="nav-link" href="#">Active</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#">Link</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#">Link</a>
    </li>
    <li class="nav-item">
      <a class="nav-link disabled" href="#">Disabled</a>
    </li>
  </ul>
</nav>
<nav class="navbar navbar-expand-sm bg-dark navbar-dark">
  <ul class="navbar-nav">
    <li class="nav-item active">
      <a class="nav-link" href="#">Active</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#">Link</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#">Link</a>
    </li>
    <li class="nav-item">
      <a class="nav-link disabled" href="#">Disabled</a>
    </li>
  </ul>
</nav>
<nav class="navbar navbar-expand-sm bg-primary navbar-dark">
  <ul class="navbar-nav">
    <li class="nav-item active">
      <a class="nav-link" href="#">Active</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#">Link</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#">Link</a>
    </li>
    <li class="nav-item">
      <a class="nav-link disabled" href="#">Disabled</a>
    </li>
  </ul>
</nav>
<nav class="navbar navbar-expand-sm bg-success navbar-dark">
  <ul class="navbar-nav">
    <li class="nav-item active">
      <a class="nav-link" href="#">Active</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#">Link</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#">Link</a>
    </li>
    <li class="nav-item">
      <a class="nav-link disabled" href="#">Disabled</a>
    </li>
  </ul>
</nav>
<nav class="navbar navbar-expand-sm bg-info navbar-dark">
  <ul class="navbar-nav">
    <li class="nav-item active">
      <a class="nav-link" href="#">Active</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#">Link</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#">Link</a>
    </li>
    <li class="nav-item">
      <a class="nav-link disabled" href="#">Disabled</a>
    </li>
  </ul>
</nav>
<nav class="navbar navbar-expand-sm bg-warning navbar-dark">
  <ul class="navbar-nav">
    <li class="nav-item active">
      <a class="nav-link" href="#">Active</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#">Link</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#">Link</a>
    </li>
    <li class="nav-item">
      <a class="nav-link disabled" href="#">Disabled</a>
    </li>
  </ul>
</nav>
<nav class="navbar navbar-expand-sm bg-danger navbar-dark">
  <ul class="navbar-nav">
    <li class="nav-item active">
      <a class="nav-link" href="#">Active</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#">Link</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#">Link</a>
    </li>
    <li class="nav-item">
      <a class="nav-link disabled" href="#">Disabled</a>
    </li>
  </ul>
</nav>
<nav class="navbar navbar-expand-sm bg-secondary navbar-dark">
  <ul class="navbar-nav">
    <li class="nav-item active">
      <a class="nav-link" href="#">Active</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#">Link</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#">Link</a>
    </li>
    <li class="nav-item">
      <a class="nav-link disabled" href="#">Disabled</a>
    </li>
  </ul>
</nav>
</body>
</html>

品牌/Logo

.navbar-brand 类用于高亮显示品牌/Logo:

实例：

<!DOCTYPE html>
<html>
<head>
  <title>Bootstrap4 实例</title>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/4.1.0/css/bootstrap.min.css">
  <script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.min.js"></script>
  <script src="https://cdn.bootcss.com/popper.js/1.12.5/umd/popper.min.js"></script>
  <script src="https://cdn.bootcss.com/bootstrap/4.1.0/js/bootstrap.min.js"></script>
</head>
<body>
<nav class="navbar navbar-expand-sm bg-dark navbar-dark">
  <!-- Brand/logo -->
  <a class="navbar-brand" href="#">Logo</a>
  <!-- Links -->
  <ul class="navbar-nav">
    <li class="nav-item">
      <a class="nav-link" href="#">Link 1</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#">Link 2</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#">Link 3</a>
    </li>
  </ul>
</nav>
<div class="container-fluid">
  <h3>品牌/Logo</h3>
  <p>.navbar-brand 类用于高亮显示品牌/Logo:</p>
</div>
</body>
</html>

如果使用图片，可以使用 .navbar-brand 类来设置图片自适应导航栏。

实例：

<!DOCTYPE html>
<html>
<head>
  <title>Bootstrap4 实例</title>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/4.1.0/css/bootstrap.min.css">
  <script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.min.js"></script>
  <script src="https://cdn.bootcss.com/popper.js/1.12.5/umd/popper.min.js"></script>
  <script src="https://cdn.bootcss.com/bootstrap/4.1.0/js/bootstrap.min.js"></script>
</head>
<body>
<nav class="navbar navbar-expand-sm bg-dark navbar-dark">
  <!-- Brand/logo -->
  <a class="navbar-brand" href="#">
    <img src="https://www.w3cschool.cn/attachments/image/20180524/1527144620597215.png" alt="logo" style="width:40px;">
  </a>
  <!-- Links -->
  <ul class="navbar-nav">
    <li class="nav-item">
      <a class="nav-link" href="#">Link 1</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#">Link 2</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#">Link 3</a>
    </li>
  </ul>
</nav>
<div class="container-fluid">
  <h3>品牌 / Logo</h3>
  <p>如果使用图片，可以使用 .navbar-brand 类来设置图片自适应导航栏。</p>
</div>
</body>
</html>

折叠导航栏

通常，小屏幕上我们都会折叠导航栏，通过点击来显示导航选项。

要创建折叠导航栏，可以在按钮上添加 class="navbar-toggle", data-toggle="collapse" 与 data-target="#thetarget" 类。然后在设置了 class="collapse navbar-collapse" 类的 div 上包裹导航内容（链接）, div 元素上的 id 匹配按钮 data-target 的上指定的 id:

实例：

<!DOCTYPE html>
<html>
<head>
  <title>Bootstrap4 实例</title>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/4.1.0/css/bootstrap.min.css">
  <script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.min.js"></script>
  <script src="https://cdn.bootcss.com/popper.js/1.12.5/umd/popper.min.js"></script>
  <script src="https://cdn.bootcss.com/bootstrap/4.1.0/js/bootstrap.min.js"></script>
</head>
<body>
<nav class="navbar navbar-expand-md bg-dark navbar-dark">
  <a class="navbar-brand" href="#">Navbar</a>
  <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#collapsibleNavbar">
    <span class="navbar-toggler-icon"></span>
  </button>
  <div class="collapse navbar-collapse" id="collapsibleNavbar">
    <ul class="navbar-nav">
      <li class="nav-item">
        <a class="nav-link" href="#">Link</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">Link</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">Link</a>
      </li>    
    </ul>
  </div>  
</nav>
<br>
<div class="container">
  <h3>折叠导航栏</h3>
  <p>通常，小屏幕上我们都会折叠导航栏，通过点击来显示导航选项。</p>
  <p>提示: 如果你删除 .navbar-expand-md 类，导航链接会一直隐藏，且切换按钮会一直显示。</p>
</div>
</body>
</html>

导航栏使用下拉菜单

导航栏上可以设置下拉菜单：

实例：

<!DOCTYPE html>
<html>
<head>
  <title>Bootstrap4 实例</title>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/4.1.0/css/bootstrap.min.css">
  <script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.min.js"></script>
  <script src="https://cdn.bootcss.com/popper.js/1.12.5/umd/popper.min.js"></script>
  <script src="https://cdn.bootcss.com/bootstrap/4.1.0/js/bootstrap.min.js"></script>
</head>
<body>
<nav class="navbar navbar-expand-sm bg-dark navbar-dark">
  <!-- Brand -->
  <a class="navbar-brand" href="#">Logo</a>
  <!-- Links -->
  <ul class="navbar-nav">
    <li class="nav-item">
      <a class="nav-link" href="#">Link 1</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#">Link 2</a>
    </li>
    <!-- Dropdown -->
    <li class="nav-item dropdown">
      <a class="nav-link dropdown-toggle" href="#" id="navbardrop" data-toggle="dropdown">
        Dropdown link
      </a>
      <div class="dropdown-menu">
        <a class="dropdown-item" href="#">Link 1</a>
        <a class="dropdown-item" href="#">Link 2</a>
        <a class="dropdown-item" href="#">Link 3</a>
      </div>
    </li>
  </ul>
</nav>
</body>
</html>

导航栏的表单与按钮

导航栏的表单 <form> 元素使用 class="form-inline" 类来排版输入框与按钮：

实例：

<!DOCTYPE html>
<html>
<head>
  <title>Bootstrap4 实例</title>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/4.1.0/css/bootstrap.min.css">
  <script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.min.js"></script>
  <script src="https://cdn.bootcss.com/popper.js/1.12.5/umd/popper.min.js"></script>
  <script src="https://cdn.bootcss.com/bootstrap/4.1.0/js/bootstrap.min.js"></script>
</head>
<body>
<nav class="navbar navbar-expand-sm bg-dark navbar-dark">
  <form class="form-inline">
    <input class="form-control" type="text" placeholder="Search">
    <button class="btn btn-success" type="button">Search</button>
  </form>
</nav>
<br>
<div class="container">
  <h3>导航栏的表单</h3>
  <p>导航栏的表单 form 元素使用 class="form-inline" 类来排版输入框与按钮：</p>
</div>
</body>
</html>

你也可以使用其他的输入框类，如 .input-group-addon 类用于在输入框前添加小标签。

实例：

<!DOCTYPE html>
<html>
<head>
  <title>Bootstrap4 实例</title>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/4.1.0/css/bootstrap.min.css">
  <script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.min.js"></script>
  <script src="https://cdn.bootcss.com/popper.js/1.12.5/umd/popper.min.js"></script>
  <script src="https://cdn.bootcss.com/bootstrap/4.1.0/js/bootstrap.min.js"></script>
</head>
<body>
<nav class="navbar navbar-expand-sm bg-dark navbar-dark">
  <form class="form-inline">
    <div class="input-group">
      <span class="input-group-addon">@</span>
      <input type="text" class="form-control" placeholder="Username">
    </div>    
  </form>
</nav>
</body>
</html>

导航栏文本

使用 .navbar-text 类来设置导航栏上非链接文本，可以保证水平对齐，颜色与内边距一样。

实例：

<!DOCTYPE html>
<html>
<head>
  <title>Bootstrap4 实例</title>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/4.1.0/css/bootstrap.min.css">
  <script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.min.js"></script>
  <script src="https://cdn.bootcss.com/popper.js/1.12.5/umd/popper.min.js"></script>
  <script src="https://cdn.bootcss.com/bootstrap/4.1.0/js/bootstrap.min.js"></script>
</head>
<body>
<nav class="navbar navbar-expand-sm bg-dark navbar-dark">
  <!-- Links -->
  <ul class="navbar-nav">
    <li class="nav-item">
      <a class="nav-link" href="#">Link 1</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#">Link 2</a>
    </li>
  </ul>
  <!-- Navbar text-->
  <span class="navbar-text">
    Navbar text
  </span>
</nav>
</body>
</html>

固定导航栏

导航栏可以固定在头部或者底部。

我们使用 .fixed-top 类来实现导航栏的顶部固定，

实例：

<!DOCTYPE html>
<html>
<head>
  <title>Bootstrap4 实例</title>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/4.1.0/css/bootstrap.min.css">
  <script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.min.js"></script>
  <script src="https://cdn.bootcss.com/popper.js/1.12.5/umd/popper.min.js"></script>
  <script src="https://cdn.bootcss.com/bootstrap/4.1.0/js/bootstrap.min.js"></script>
</head>
<body  style="height:1500px">
<nav class="navbar navbar-expand-sm bg-dark navbar-dark fixed-top">
  <a class="navbar-brand" href="#">Logo</a>
  <ul class="navbar-nav">
    <li class="nav-item">
      <a class="nav-link" href="#">Link</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#">Link</a>
    </li>
  </ul>
</nav>
<div class="container-fluid" style="margin-top:80px">
  <h3>固定导航栏</h3>
  <p>导航栏可以固定在头部或者底部。</p>
  <h1>滚动页面查看效果。</h1>
</div>
</body>
</html>

.fixed-bottom 类用于设置导航栏固定在底部：

<!DOCTYPE html>
<html>
<head>
  <title>Bootstrap 实例</title>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="stylesheet" href="https://cdn.staticfile.org/twitter-bootstrap/4.3.1/css/bootstrap.min.css">
  <script src="https://cdn.staticfile.org/jquery/3.2.1/jquery.min.js"></script>
  <script src="https://cdn.staticfile.org/popper.js/1.15.0/umd/popper.min.js"></script>
  <script src="https://cdn.staticfile.org/twitter-bootstrap/4.3.1/js/bootstrap.min.js"></script>
</head>
<body style="height:1500px">

<nav class="navbar navbar-expand-sm bg-dark navbar-dark fixed-bottom">
  <a class="navbar-brand" href="#">Logo</a>
  <ul class="navbar-nav">
    <li class="nav-item">
      <a class="nav-link" href="javascript:void(0)">Link</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="javascript:void(0)">Link</a>
    </li>
  </ul>
</nav>

<div class="container-fluid">
  <h3>底部固定导航栏</h3>
  <p>导航栏可以固定在头部或者底部。</p>
  <h1>滚动页面查看效果。</h1>
</div>

</body>
</html>

w3cschool 编程狮，随时随地学编程

Bootstrap4 导航栏

基础导航栏创建

垂直导航栏

不同颜色导航栏

品牌/Logo

折叠导航栏

导航栏使用下拉菜单

导航栏的表单与按钮

导航栏文本

固定导航栏