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Bootstrap 强大的响应式导航标题导航栏的文档和示例。包括对品牌、导航等的支持,包括对我们的折叠插件的支持。

怎么运行的

在开始使用导航栏之前,您需要了解以下内容:

  • 导航栏需要.navbar.navbar-expand{-sm|-md|-lg|-xl|-xxl}来支持响应式折叠和配色方案类。
  • 默认情况下,导航栏及其内容是流动的。更改容器以不同方式限制其水平宽度。
  • 使用我们的spacingflex实用程序类来控制导航栏中的间距和对齐方式。
  • 默认情况下,导航栏是响应式的,但您可以轻松修改它们以更改它。响应式行为取决于我们的折叠 JavaScript 插件。
  • 通过使用<nav>元素确保可访问性,或者,如果使用更通用的元素(例如 <div>),请将role="navigation"添加到每个导航栏以明确将其标识为辅助技术用户的地标区域。
  • 通过aria-current="page"用于当前页面或aria-current="true"集合中的当前项目来指示当前项目。
  • v5.2.0 中的新功能:导航栏可以使用作用域为.navbar基类的 CSS 变量作为主题。.navbar-light已被弃用.navbar-dark并被重写以覆盖 CSS 变量而不是添加额外的样式。
该组件的动画效果依赖于prefers-reduced-motion媒体查询。请参阅我们的辅助功能文档的减少运动部分

支持的内容

导航栏内置了对少数子组件的支持。根据需要从以下选项中选择:

  • .navbar-brand为您的公司、产品或项目名称。
  • .navbar-nav用于全高度和轻量级导航(包括对下拉菜单的支持)。
  • .navbar-toggler用于我们的折叠插件和其他导航切换行为。
  • 用于任何表单控件和操作的 Flex 和间距实用程序。
  • .navbar-text用于添加垂直居中的文本字符串。
  • .collapse.navbar-collapse用于按父断点分组和隐藏导航栏内容。
  • 添加一个选项.navbar-scroll来设置max-height滚动展开的导航栏内容

这是响应式浅色主题导航栏中包含的所有子组件的示例,该导航栏会在lg(大)断点处自动折叠。

HTML
<nav class="navbar navbar-expand-lg bg-body-tertiary">
  <div class="container-fluid">
    <a class="navbar-brand" href="#">Navbar</a>
    <button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-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 me-auto mb-2 mb-lg-0">
        <li class="nav-item">
          <a class="nav-link active" aria-current="page" href="#">Home</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="#" role="button" data-bs-toggle="dropdown" aria-expanded="false">
            Dropdown
          </a>
          <ul class="dropdown-menu">
            <li><a class="dropdown-item" href="#">Action</a></li>
            <li><a class="dropdown-item" href="#">Another action</a></li>
            <li><hr class="dropdown-divider"></li>
            <li><a class="dropdown-item" href="#">Something else here</a></li>
          </ul>
        </li>
        <li class="nav-item">
          <a class="nav-link disabled">Disabled</a>
        </li>
      </ul>
      <form class="d-flex" role="search">
        <input class="form-control me-2" type="search" placeholder="Search" aria-label="Search">
        <button class="btn btn-outline-success" type="submit">Search</button>
      </form>
    </div>
  </div>
</nav>

此示例使用背景( bg-body-tertiary) 和间距( me-auto, mb-2, mb-lg-0, me-2) 实用程序类。

品牌

.navbar-brand可以应用于大多数元素,但锚点效果最好,因为某些元素可能需要实用程序类或自定义样式。

文本

在具有.navbar-brand该类的元素中添加您的文本。

HTML
<!-- As a link -->
<nav class="navbar bg-body-tertiary">
  <div class="container-fluid">
    <a class="navbar-brand" href="#">Navbar</a>
  </div>
</nav>

<!-- As a heading -->
<nav class="navbar bg-body-tertiary">
  <div class="container-fluid">
    <span class="navbar-brand mb-0 h1">Navbar</span>
  </div>
</nav>

图片

您可以将 中的文本替换.navbar-brand<img>

HTML
<nav class="navbar bg-body-tertiary">
  <div class="container">
    <a class="navbar-brand" href="#">
      <img src="/docs/5.3/assets/brand/bootstrap-logo.svg" alt="Bootstrap" width="30" height="24">
    </a>
  </div>
</nav>

图片和文字

您还可以使用一些额外的实用程序同时添加图像和文本。请注意.d-inline-block.align-text-top放在<img>上.

HTML
<nav class="navbar bg-body-tertiary">
  <div class="container-fluid">
    <a class="navbar-brand" href="#">
      <img src="/docs/5.3/assets/brand/bootstrap-logo.svg" alt="Logo" width="30" height="24" class="d-inline-block align-text-top">
      Bootstrap
    </a>
  </div>
</nav>

导航栏导航链接建立在我们的.nav选项之上,带有自己的修饰符类,并且需要使用切换器来实现适当的响应式样式。导航栏中的导航也将增长以占据尽可能多的水平空间,以保持导航栏内容安全对齐。

添加.active类到.nav-link以指示当前页面。

请注意,您还应该在选中的.nav-link上添加aria-current属性。

HTML
<nav class="navbar navbar-expand-lg bg-body-tertiary">
  <div class="container-fluid">
    <a class="navbar-brand" href="#">Navbar</a>
    <button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-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 active" aria-current="page" href="#">Home</a>
        </li>
        <li class="nav-item">
          <a class="nav-link" href="#">Features</a>
        </li>
        <li class="nav-item">
          <a class="nav-link" href="#">Pricing</a>
        </li>
        <li class="nav-item">
          <a class="nav-link disabled">Disabled</a>
        </li>
      </ul>
    </div>
  </div>
</nav>

因为我们为我们的导航使用类,如果你愿意,你可以完全避免基于列表的方法。

HTML
<nav class="navbar navbar-expand-lg bg-body-tertiary">
  <div class="container-fluid">
    <a class="navbar-brand" href="#">Navbar</a>
    <button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarNavAltMarkup" aria-controls="navbarNavAltMarkup" aria-expanded="false" aria-label="Toggle navigation">
      <span class="navbar-toggler-icon"></span>
    </button>
    <div class="collapse navbar-collapse" id="navbarNavAltMarkup">
      <div class="navbar-nav">
        <a class="nav-link active" aria-current="page" href="#">Home</a>
        <a class="nav-link" href="#">Features</a>
        <a class="nav-link" href="#">Pricing</a>
        <a class="nav-link disabled">Disabled</a>
      </div>
    </div>
  </div>
</nav>

您还可以在导航栏中使用下拉菜单。下拉菜单需要一个包装元素来定位,所以请务必使用如下所示的独立.nav-item.nav-link嵌套元素。

HTML
<nav class="navbar navbar-expand-lg bg-body-tertiary">
  <div class="container-fluid">
    <a class="navbar-brand" href="#">Navbar</a>
    <button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarNavDropdown" aria-controls="navbarNavDropdown" aria-expanded="false" aria-label="Toggle navigation">
      <span class="navbar-toggler-icon"></span>
    </button>
    <div class="collapse navbar-collapse" id="navbarNavDropdown">
      <ul class="navbar-nav">
        <li class="nav-item">
          <a class="nav-link active" aria-current="page" href="#">Home</a>
        </li>
        <li class="nav-item">
          <a class="nav-link" href="#">Features</a>
        </li>
        <li class="nav-item">
          <a class="nav-link" href="#">Pricing</a>
        </li>
        <li class="nav-item dropdown">
          <a class="nav-link dropdown-toggle" href="#" role="button" data-bs-toggle="dropdown" aria-expanded="false">
            Dropdown link
          </a>
          <ul class="dropdown-menu">
            <li><a class="dropdown-item" href="#">Action</a></li>
            <li><a class="dropdown-item" href="#">Another action</a></li>
            <li><a class="dropdown-item" href="#">Something else here</a></li>
          </ul>
        </li>
      </ul>
    </div>
  </div>
</nav>

表单

在导航栏中放置各种表单控件和组件:

HTML
<nav class="navbar bg-body-tertiary">
  <div class="container-fluid">
    <form class="d-flex" role="search">
      <input class="form-control me-2" type="search" placeholder="Search" aria-label="Search">
      <button class="btn btn-outline-success" type="submit">Search</button>
    </form>
  </div>
</nav>

.navbar使用 flex 布局的直接子元素将默认为justify-content: space-between. 根据需要使用其他flex 实用程序来调整此行为。

HTML
<nav class="navbar bg-body-tertiary">
  <div class="container-fluid">
    <a class="navbar-brand">Navbar</a>
    <form class="d-flex" role="search">
      <input class="form-control me-2" type="search" placeholder="Search" aria-label="Search">
      <button class="btn btn-outline-success" type="submit">Search</button>
    </form>
  </div>
</nav>

输入组也起作用。如果您的导航栏是一个完整的表单,或者主要是一个表单,您可以使用该<form>元素作为容器并保存一些 HTML。

HTML
<nav class="navbar bg-body-tertiary">
  <form class="container-fluid">
    <div class="input-group">
      <span class="input-group-text" id="basic-addon1">@</span>
      <input type="text" class="form-control" placeholder="Username" aria-label="Username" aria-describedby="basic-addon1">
    </div>
  </form>
</nav>

这些导航栏表单也支持各种按钮。这也是一个很好的提醒,垂直对齐实用程序可用于对齐不同大小的元素。

HTML
<nav class="navbar bg-body-tertiary">
  <form class="container-fluid justify-content-start">
    <button class="btn btn-outline-success me-2" type="button">Main button</button>
    <button class="btn btn-sm btn-outline-secondary" type="button">Smaller button</button>
  </form>
</nav>

文本

导航栏可以在.navbar-text的帮助下包含一些文本。此类调整文本字符串的垂直对齐方式和水平间距。

HTML
<nav class="navbar bg-body-tertiary">
  <div class="container-fluid">
    <span class="navbar-text">
      Navbar text with an inline element
    </span>
  </div>
</nav>

根据需要与其他组件和实用程序混合搭配。

HTML
<nav class="navbar navbar-expand-lg bg-body-tertiary">
  <div class="container-fluid">
    <a class="navbar-brand" href="#">Navbar w/ text</a>
    <button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarText" aria-controls="navbarText" aria-expanded="false" aria-label="Toggle navigation">
      <span class="navbar-toggler-icon"></span>
    </button>
    <div class="collapse navbar-collapse" id="navbarText">
      <ul class="navbar-nav me-auto mb-2 mb-lg-0">
        <li class="nav-item">
          <a class="nav-link active" aria-current="page" href="#">Home</a>
        </li>
        <li class="nav-item">
          <a class="nav-link" href="#">Features</a>
        </li>
        <li class="nav-item">
          <a class="nav-link" href="#">Pricing</a>
        </li>
      </ul>
      <span class="navbar-text">
        Navbar text with an inline element
      </span>
    </div>
  </div>
</nav>

配色方案

v5.3.0 中新的深色导航栏——我们已经弃用.navbar-dark了新的data-bs-theme="dark". 添加data-bs-theme="dark".navbar以启用特定于组件的颜色模式。详细了解我们的颜色模式。


v5.2.0 中的新功能 — Navbar 主题现在由 CSS 变量提供支持并且.navbar-light已被弃用。CSS 变量应用于.navbar,默认为“浅色”外观,并且可以被覆盖.navbar-dark

由于 Bootstrap 结合了 Sass 和 CSS 变量,导航栏主题比以往任何时候都更容易。默认是我们的“浅色导航栏”,用于浅色背景,但您也可以应用.navbar-dark为深色背景。然后,使用.bg-*实用程序进行自定义。

<nav class="navbar bg-dark" data-bs-theme="dark">
  <!-- Navbar content -->
</nav>

<nav class="navbar bg-primary" data-bs-theme="dark">
  <!-- Navbar content -->
</nav>

<nav class="navbar" style="background-color: #e3f2fd;">
  <!-- Navbar content -->
</nav>

容器

虽然这不是必需的,但您可以将导航栏包裹在.container中以使其在页面上居中——但请注意,内部容器仍然是必需的。或者您可以在.navbar中添加一个容器,以仅将固定或静态顶部导航栏的内容居中。

HTML
<div class="container">
  <nav class="navbar navbar-expand-lg bg-body-tertiary">
    <div class="container-fluid">
      <a class="navbar-brand" href="#">Navbar</a>
    </div>
  </nav>
</div>

使用任何响应式容器来更改导航栏中内容的显示宽度。

HTML
<nav class="navbar navbar-expand-lg bg-body-tertiary">
  <div class="container-md">
    <a class="navbar-brand" href="#">Navbar</a>
  </div>
</nav>

位置

使用我们的位置实用程序将导航栏放置在非静态位置。从固定到顶部、固定到底部、粘到顶部(滚动页面直到到达顶部,然后停留在那里)或粘到底部(滚动到页面底部,然后停留)中选择那里)。

固定导航栏使用position: fixed,这意味着它们是从 DOM 的正常流中提取的,并且可能需要自定义 CSS(例如,padding-top<body>上)以防止与其他元素重叠。

HTML
<nav class="navbar bg-body-tertiary">
  <div class="container-fluid">
    <a class="navbar-brand" href="#">Default</a>
  </div>
</nav>
HTML
<nav class="navbar fixed-top bg-body-tertiary">
  <div class="container-fluid">
    <a class="navbar-brand" href="#">Fixed top</a>
  </div>
</nav>
HTML
<nav class="navbar fixed-bottom bg-body-tertiary">
  <div class="container-fluid">
    <a class="navbar-brand" href="#">Fixed bottom</a>
  </div>
</nav>
HTML
<nav class="navbar sticky-top bg-body-tertiary">
  <div class="container-fluid">
    <a class="navbar-brand" href="#">Sticky top</a>
  </div>
</nav>
HTML
<nav class="navbar sticky-bottom bg-body-tertiary">
  <div class="container-fluid">
    <a class="navbar-brand" href="#">Sticky bottom</a>
  </div>
</nav>

滚动

添加.navbar-nav-scroll.navbar-nav(或其他导航栏子组件)以在折叠的导航栏的可切换内容中启用垂直滚动。默认情况下,滚动在75vh开始(或视口高度的 75%),但您可以使用本地 CSS 自定义属性--bs-navbar-height或自定义样式覆盖它。当导航栏展开时,在较大的视口中,内容将像在默认导航栏中一样显示。

请注意,此行为有一个潜在的缺点——当overflow设置overflow-y: auto(需要在此处滚动内容)时,overflow-x相当于auto,这将裁剪一些水平内容。

这是一个使用.navbar-nav-scrollstyle="--bs-scroll-height: 100px;"的示例导航栏,带有一些额外的边距实用程序以获得最佳间距。

HTML
<nav class="navbar navbar-expand-lg bg-body-tertiary">
  <div class="container-fluid">
    <a class="navbar-brand" href="#">Navbar scroll</a>
    <button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarScroll" aria-controls="navbarScroll" aria-expanded="false" aria-label="Toggle navigation">
      <span class="navbar-toggler-icon"></span>
    </button>
    <div class="collapse navbar-collapse" id="navbarScroll">
      <ul class="navbar-nav me-auto my-2 my-lg-0 navbar-nav-scroll" style="--bs-scroll-height: 100px;">
        <li class="nav-item">
          <a class="nav-link active" aria-current="page" href="#">Home</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="#" role="button" data-bs-toggle="dropdown" aria-expanded="false">
            Link
          </a>
          <ul class="dropdown-menu">
            <li><a class="dropdown-item" href="#">Action</a></li>
            <li><a class="dropdown-item" href="#">Another action</a></li>
            <li><hr class="dropdown-divider"></li>
            <li><a class="dropdown-item" href="#">Something else here</a></li>
          </ul>
        </li>
        <li class="nav-item">
          <a class="nav-link disabled">Link</a>
        </li>
      </ul>
      <form class="d-flex" role="search">
        <input class="form-control me-2" type="search" placeholder="Search" aria-label="Search">
        <button class="btn btn-outline-success" type="submit">Search</button>
      </form>
    </div>
  </div>
</nav>

响应式行为

导航栏可以使用.navbar-toggler.navbar-collapse.navbar-expand{-sm|-md|-lg|-xl|-xxl}类来确定它们的内容何时折叠在按钮后面。结合其他实用程序,您可以轻松选择何时显示或隐藏特定元素。

对于永不折叠的导航栏,在导航栏上添加.navbar-expand类。对于总是折叠的导航栏,不要添加任何.navbar-expand类。

切换器

默认情况下,导航栏切换器是左对齐的,但如果它们跟在像.navbar-brand这样的兄弟元素之后,它们将自动对齐到最右边。反转标记将反转切换器的位置。以下是不同切换样式的示例。

.navbar-brand在最小断点处没有显示:

HTML
<nav class="navbar navbar-expand-lg bg-body-tertiary">
  <div class="container-fluid">
    <button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarTogglerDemo01" aria-controls="navbarTogglerDemo01" aria-expanded="false" aria-label="Toggle navigation">
      <span class="navbar-toggler-icon"></span>
    </button>
    <div class="collapse navbar-collapse" id="navbarTogglerDemo01">
      <a class="navbar-brand" href="#">Hidden brand</a>
      <ul class="navbar-nav me-auto mb-2 mb-lg-0">
        <li class="nav-item">
          <a class="nav-link active" aria-current="page" href="#">Home</a>
        </li>
        <li class="nav-item">
          <a class="nav-link" href="#">Link</a>
        </li>
        <li class="nav-item">
          <a class="nav-link disabled">Disabled</a>
        </li>
      </ul>
      <form class="d-flex" role="search">
        <input class="form-control me-2" type="search" placeholder="Search" aria-label="Search">
        <button class="btn btn-outline-success" type="submit">Search</button>
      </form>
    </div>
  </div>
</nav>

左侧显示品牌名称,右侧显示切换器:

HTML
<nav class="navbar navbar-expand-lg bg-body-tertiary">
  <div class="container-fluid">
    <a class="navbar-brand" href="#">Navbar</a>
    <button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarTogglerDemo02" aria-controls="navbarTogglerDemo02" aria-expanded="false" aria-label="Toggle navigation">
      <span class="navbar-toggler-icon"></span>
    </button>
    <div class="collapse navbar-collapse" id="navbarTogglerDemo02">
      <ul class="navbar-nav me-auto mb-2 mb-lg-0">
        <li class="nav-item">
          <a class="nav-link active" aria-current="page" href="#">Home</a>
        </li>
        <li class="nav-item">
          <a class="nav-link" href="#">Link</a>
        </li>
        <li class="nav-item">
          <a class="nav-link disabled">Disabled</a>
        </li>
      </ul>
      <form class="d-flex" role="search">
        <input class="form-control me-2" type="search" placeholder="Search" aria-label="Search">
        <button class="btn btn-outline-success" type="submit">Search</button>
      </form>
    </div>
  </div>
</nav>

左侧带有切换器,右侧带有品牌名称:

HTML
<nav class="navbar navbar-expand-lg bg-body-tertiary">
  <div class="container-fluid">
    <button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarTogglerDemo03" aria-controls="navbarTogglerDemo03" aria-expanded="false" aria-label="Toggle navigation">
      <span class="navbar-toggler-icon"></span>
    </button>
    <a class="navbar-brand" href="#">Navbar</a>
    <div class="collapse navbar-collapse" id="navbarTogglerDemo03">
      <ul class="navbar-nav me-auto mb-2 mb-lg-0">
        <li class="nav-item">
          <a class="nav-link active" aria-current="page" href="#">Home</a>
        </li>
        <li class="nav-item">
          <a class="nav-link" href="#">Link</a>
        </li>
        <li class="nav-item">
          <a class="nav-link disabled">Disabled</a>
        </li>
      </ul>
      <form class="d-flex" role="search">
        <input class="form-control me-2" type="search" placeholder="Search" aria-label="Search">
        <button class="btn btn-outline-success" type="submit">Search</button>
      </form>
    </div>
  </div>
</nav>

外部内容

有时您希望使用折叠插件触发位于.navbar之外的元素. 我们的插件适用于iddata-bs-target匹配,所以很容易做到!

HTML
<div class="collapse" id="navbarToggleExternalContent">
  <div class="bg-dark p-4">
    <h5 class="text-white h4">Collapsed content</h5>
    <span class="text-muted">Toggleable via the navbar brand.</span>
  </div>
</div>
<nav class="navbar navbar-dark bg-dark">
  <div class="container-fluid">
    <button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarToggleExternalContent" aria-controls="navbarToggleExternalContent" aria-expanded="false" aria-label="Toggle navigation">
      <span class="navbar-toggler-icon"></span>
    </button>
  </div>
</nav>

执行此操作时,我们建议包含额外的 JavaScript,以便在容器打开时以编程方式将焦点移动到容器。否则,键盘用户和辅助技术用户可能很难找到新显示的内容 - 特别是如果打开的容器位于文档结构中的切换器之前。我们还建议确保切换器具有aria-controls指向id内容容器的属性。从理论上讲,这允许辅助技术用户直接从切换器跳转到它控制的容器——但目前对此的支持还很不完整。

侧边栏组件

使用offcanvas 组件将展开和折叠的导航栏转换为 offcanvas 抽屉。我们扩展了 offcanvas 默认样式并使用我们的.navbar-expand-*类来创建动态且灵活的导航侧边栏。

在下面的示例中,要创建一个始终在所有断点处折叠的 offcanvas 导航栏,请.navbar-expand-*完全省略该类。

HTML
<nav class="navbar bg-body-tertiary fixed-top">
  <div class="container-fluid">
    <a class="navbar-brand" href="#">Offcanvas navbar</a>
    <button class="navbar-toggler" type="button" data-bs-toggle="offcanvas" data-bs-target="#offcanvasNavbar" aria-controls="offcanvasNavbar">
      <span class="navbar-toggler-icon"></span>
    </button>
    <div class="offcanvas offcanvas-end" tabindex="-1" id="offcanvasNavbar" aria-labelledby="offcanvasNavbarLabel">
      <div class="offcanvas-header">
        <h5 class="offcanvas-title" id="offcanvasNavbarLabel">Offcanvas</h5>
        <button type="button" class="btn-close" data-bs-dismiss="offcanvas" aria-label="Close"></button>
      </div>
      <div class="offcanvas-body">
        <ul class="navbar-nav justify-content-end flex-grow-1 pe-3">
          <li class="nav-item">
            <a class="nav-link active" aria-current="page" href="#">Home</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="#" role="button" data-bs-toggle="dropdown" aria-expanded="false">
              Dropdown
            </a>
            <ul class="dropdown-menu">
              <li><a class="dropdown-item" href="#">Action</a></li>
              <li><a class="dropdown-item" href="#">Another action</a></li>
              <li>
                <hr class="dropdown-divider">
              </li>
              <li><a class="dropdown-item" href="#">Something else here</a></li>
            </ul>
          </li>
        </ul>
        <form class="d-flex mt-3" role="search">
          <input class="form-control me-2" type="search" placeholder="Search" aria-label="Search">
          <button class="btn btn-outline-success" type="submit">Search</button>
        </form>
      </div>
    </div>
  </div>
</nav>

要创建在特定断点(如 lg)处扩展为普通导航栏的 offcanvas 导航栏,请使用.navbar-expand-lg

<nav class="navbar navbar-expand-lg bg-body-tertiary fixed-top">
  <a class="navbar-brand" href="#">Offcanvas navbar</a>
  <button class="navbar-toggler" type="button" data-bs-toggle="offcanvas" data-bs-target="#navbarOffcanvasLg" aria-controls="navbarOffcanvasLg">
    <span class="navbar-toggler-icon"></span>
  </button>
  <div class="offcanvas offcanvas-end" tabindex="-1" id="navbarOffcanvasLg" aria-labelledby="navbarOffcanvasLgLabel">
    ...
  </div>
</nav>

在深色导航栏中使用 offcanvas 时,请注意您可能需要在 offcanvas 内容上设置深色背景以避免文本变得难以辨认。在下面的示例中,我们将.navbar-dark.bg-dark添加到.navbar.text-bg-dark添加到 .offcanvas.dropdown-menu-dark添加到.dropdown-menu.btn-close-white添加到.btn-close以使用深色画布进行适当的样式设置。

HTML
<nav class="navbar navbar-dark bg-dark fixed-top">
  <div class="container-fluid">
    <a class="navbar-brand" href="#">Offcanvas dark navbar</a>
    <button class="navbar-toggler" type="button" data-bs-toggle="offcanvas" data-bs-target="#offcanvasDarkNavbar" aria-controls="offcanvasDarkNavbar">
      <span class="navbar-toggler-icon"></span>
    </button>
    <div class="offcanvas offcanvas-end text-bg-dark" tabindex="-1" id="offcanvasDarkNavbar" aria-labelledby="offcanvasDarkNavbarLabel">
      <div class="offcanvas-header">
        <h5 class="offcanvas-title" id="offcanvasDarkNavbarLabel">Dark offcanvas</h5>
        <button type="button" class="btn-close btn-close-white" data-bs-dismiss="offcanvas" aria-label="Close"></button>
      </div>
      <div class="offcanvas-body">
        <ul class="navbar-nav justify-content-end flex-grow-1 pe-3">
          <li class="nav-item">
            <a class="nav-link active" aria-current="page" href="#">Home</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="#" role="button" data-bs-toggle="dropdown" aria-expanded="false">
              Dropdown
            </a>
            <ul class="dropdown-menu dropdown-menu-dark">
              <li><a class="dropdown-item" href="#">Action</a></li>
              <li><a class="dropdown-item" href="#">Another action</a></li>
              <li>
                <hr class="dropdown-divider">
              </li>
              <li><a class="dropdown-item" href="#">Something else here</a></li>
            </ul>
          </li>
        </ul>
        <form class="d-flex mt-3" role="search">
          <input class="form-control me-2" type="search" placeholder="Search" aria-label="Search">
          <button class="btn btn-success" type="submit">Search</button>
        </form>
      </div>
    </div>
  </div>
</nav>

CSS

变量

添加于 v5.2.0

作为 Bootstrap 不断发展的 CSS 变量方法的一部分,导航栏现在使用本地 CSS 变量.navbar来增强实时定制。CSS 变量的值是通过 Sass 设置的,因此仍然支持 Sass 自定义。

  --#{$prefix}navbar-padding-x: #{if($navbar-padding-x == null, 0, $navbar-padding-x)};
  --#{$prefix}navbar-padding-y: #{$navbar-padding-y};
  --#{$prefix}navbar-color: #{$navbar-light-color};
  --#{$prefix}navbar-hover-color: #{$navbar-light-hover-color};
  --#{$prefix}navbar-disabled-color: #{$navbar-light-disabled-color};
  --#{$prefix}navbar-active-color: #{$navbar-light-active-color};
  --#{$prefix}navbar-brand-padding-y: #{$navbar-brand-padding-y};
  --#{$prefix}navbar-brand-margin-end: #{$navbar-brand-margin-end};
  --#{$prefix}navbar-brand-font-size: #{$navbar-brand-font-size};
  --#{$prefix}navbar-brand-color: #{$navbar-light-brand-color};
  --#{$prefix}navbar-brand-hover-color: #{$navbar-light-brand-hover-color};
  --#{$prefix}navbar-nav-link-padding-x: #{$navbar-nav-link-padding-x};
  --#{$prefix}navbar-toggler-padding-y: #{$navbar-toggler-padding-y};
  --#{$prefix}navbar-toggler-padding-x: #{$navbar-toggler-padding-x};
  --#{$prefix}navbar-toggler-font-size: #{$navbar-toggler-font-size};
  --#{$prefix}navbar-toggler-icon-bg: #{escape-svg($navbar-light-toggler-icon-bg)};
  --#{$prefix}navbar-toggler-border-color: #{$navbar-light-toggler-border-color};
  --#{$prefix}navbar-toggler-border-radius: #{$navbar-toggler-border-radius};
  --#{$prefix}navbar-toggler-focus-width: #{$navbar-toggler-focus-width};
  --#{$prefix}navbar-toggler-transition: #{$navbar-toggler-transition};
  

一些额外的 CSS 变量也存在于.navbar-nav

  --#{$prefix}nav-link-padding-x: 0;
  --#{$prefix}nav-link-padding-y: #{$nav-link-padding-y};
  @include rfs($nav-link-font-size, --#{$prefix}nav-link-font-size);
  --#{$prefix}nav-link-font-weight: #{$nav-link-font-weight};
  --#{$prefix}nav-link-color: var(--#{$prefix}navbar-color);
  --#{$prefix}nav-link-hover-color: var(--#{$prefix}navbar-hover-color);
  --#{$prefix}nav-link-disabled-color: var(--#{$prefix}navbar-disabled-color);
  

通过 CSS 变量进行自定义可以在.navbar-dark类上看到,我们在其中覆盖特定值而不添加重复的 CSS 选择器。

  --#{$prefix}navbar-color: #{$navbar-dark-color};
  --#{$prefix}navbar-hover-color: #{$navbar-dark-hover-color};
  --#{$prefix}navbar-disabled-color: #{$navbar-dark-disabled-color};
  --#{$prefix}navbar-active-color: #{$navbar-dark-active-color};
  --#{$prefix}navbar-brand-color: #{$navbar-dark-brand-color};
  --#{$prefix}navbar-brand-hover-color: #{$navbar-dark-brand-hover-color};
  --#{$prefix}navbar-toggler-border-color: #{$navbar-dark-toggler-border-color};
  --#{$prefix}navbar-toggler-icon-bg: #{escape-svg($navbar-dark-toggler-icon-bg)};
  

Sass 变量

所有导航栏的变量:

$navbar-padding-y:                  $spacer * .5;
$navbar-padding-x:                  null;

$navbar-nav-link-padding-x:         .5rem;

$navbar-brand-font-size:            $font-size-lg;
// Compute the navbar-brand padding-y so the navbar-brand will have the same height as navbar-text and nav-link
$nav-link-height:                   $font-size-base * $line-height-base + $nav-link-padding-y * 2;
$navbar-brand-height:               $navbar-brand-font-size * $line-height-base;
$navbar-brand-padding-y:            ($nav-link-height - $navbar-brand-height) * .5;
$navbar-brand-margin-end:           1rem;

$navbar-toggler-padding-y:          .25rem;
$navbar-toggler-padding-x:          .75rem;
$navbar-toggler-font-size:          $font-size-lg;
$navbar-toggler-border-radius:      $btn-border-radius;
$navbar-toggler-focus-width:        $btn-focus-width;
$navbar-toggler-transition:         box-shadow .15s ease-in-out;

$navbar-light-color:                rgba(var(--#{$prefix}emphasis-color-rgb), .65);
$navbar-light-hover-color:          rgba(var(--#{$prefix}emphasis-color-rgb), .8);
$navbar-light-active-color:         rgba(var(--#{$prefix}emphasis-color-rgb), 1);
$navbar-light-disabled-color:       rgba(var(--#{$prefix}emphasis-color-rgb), .3);
$navbar-light-toggler-icon-bg:      url("data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 30 30'><path stroke='#{rgba($body-color, .75)}' stroke-linecap='round' stroke-miterlimit='10' stroke-width='2' d='M4 7h22M4 15h22M4 23h22'/></svg>");
$navbar-light-toggler-border-color: rgba(var(--#{$prefix}emphasis-color-rgb), .15);
$navbar-light-brand-color:          $navbar-light-active-color;
$navbar-light-brand-hover-color:    $navbar-light-active-color;

深色导航栏的变量:

$navbar-dark-color:                 rgba($white, .55);
$navbar-dark-hover-color:           rgba($white, .75);
$navbar-dark-active-color:          $white;
$navbar-dark-disabled-color:        rgba($white, .25);
$navbar-dark-toggler-icon-bg:       url("data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 30 30'><path stroke='#{$navbar-dark-color}' stroke-linecap='round' stroke-miterlimit='10' stroke-width='2' d='M4 7h22M4 15h22M4 23h22'/></svg>");
$navbar-dark-toggler-border-color:  rgba($white, .1);
$navbar-dark-brand-color:           $navbar-dark-active-color;
$navbar-dark-brand-hover-color:     $navbar-dark-active-color;

Sass循环

响应式导航栏展开/折叠类(例如,.navbar-expand-lg)与$breakpoints地图结合并通过循环生成scss/_navbar.scss

// Generate series of `.navbar-expand-*` responsive classes for configuring
// where your navbar collapses.
.navbar-expand {
  @each $breakpoint in map-keys($grid-breakpoints) {
    $next: breakpoint-next($breakpoint, $grid-breakpoints);
    $infix: breakpoint-infix($next, $grid-breakpoints);

    // stylelint-disable-next-line scss/selector-no-union-class-name
    &#{$infix} {
      @include media-breakpoint-up($next) {
        flex-wrap: nowrap;
        justify-content: flex-start;

        .navbar-nav {
          flex-direction: row;

          .dropdown-menu {
            position: absolute;
          }

          .nav-link {
            padding-right: var(--#{$prefix}navbar-nav-link-padding-x);
            padding-left: var(--#{$prefix}navbar-nav-link-padding-x);
          }
        }

        .navbar-nav-scroll {
          overflow: visible;
        }

        .navbar-collapse {
          display: flex !important; // stylelint-disable-line declaration-no-important
          flex-basis: auto;
        }

        .navbar-toggler {
          display: none;
        }

        .offcanvas {
          // stylelint-disable declaration-no-important
          position: static;
          z-index: auto;
          flex-grow: 1;
          width: auto !important;
          height: auto !important;
          visibility: visible !important;
          background-color: transparent !important;
          border: 0 !important;
          transform: none !important;
          @include box-shadow(none);
          @include transition(none);
          // stylelint-enable declaration-no-important

          .offcanvas-header {
            display: none;
          }

          .offcanvas-body {
            display: flex;
            flex-grow: 0;
            padding: 0;
            overflow-y: visible;
          }
        }
      }
    }
  }
}