Bootstrap 响应式导航栏

导航栏是一个很好的功能，是 Bootstrap 网站的一个突出特点。导航栏在您的应用或网站中作为导航页头的响应式基础组件。导航栏在移动设备的视图中是折叠的，随着可用视口宽度的增加，导航栏也会水平展开。在 Bootstrap 导航栏的核心中，导航栏包括了站点名称和基本的导航定义样式。

默认的导航栏

创建一个默认的导航栏的步骤如下：

• 向
  标签添加 class .navbar、.navbar-default。
• 向上面的元素添加 role="navigation"，有助于增加可访问性。
• 向
  元素添加一个标题 class .navbar-header，内部包含了带有 class navbar-brand 的 元素。这会让文本看起来更大一号。
• 为了向导航栏添加链接，只需要简单地添加带有 class .nav、.navbar-nav 的无序列表即可。

下面的实例演示了这点：

实例

< nav class = " navbar navbar-default " role = " navigation " >  

    < div class = " container-fluid " >  

        < div class = " navbar-header " >  

            < a class = " navbar-brand " href = " # " > 菜鸟教程 a >  

         div >  

        < div >  

            < ul class = " nav navbar-nav " >  

                < li class = " active " > < a href = " # " > iOS a > li >  

                < li > < a href = " # " > SVN a > li >  

                < li class = " dropdown " >  

                     href = " # " class = " dropdown-toggle " data-toggle = " dropdown " > Java

                        < b class = " caret " > b >  

                     a >  

                    < ul class = " dropdown-menu " >  

                        < li > < a href = " # " > jmeter a > li >  

                        < li > < a href = " # " > EJB a > li >  

                        < li > < a href = " # " > Jasper Report a > li >  

                        < li class = " divider " > li >  

                        < li > < a href = " # " > 分离的链接 a > li >  

                        < li class = " divider " > li >  

                        < li > < a href = " # " > 另一个分离的链接 a > li >  

                     ul >  

                 li >  

             ul >  

         div >  

     div >

nav >

结果如下所示：

---

响应式的导航栏

为了给导航栏添加响应式特性，您要折叠的内容必须包裹在带有 class .collapse、.navbar-collapse 的

中。折叠起来的导航栏实际上是一个带有 class .navbar-toggle 及两个 data- 元素的按钮。第一个是 data-toggle，用于告诉 JavaScript 需要对按钮做什么，第二个是 data-target，指示要切换到哪一个元素。三个带有 class .icon-bar 的 创建所谓的汉堡按钮。这些会切换为 .nav-collapse 

中的元素。为了实现以上这些功能，您必须包含 Bootstrap 折叠（Collapse）插件。

下面的实例演示了这点：

实例

< nav class = " navbar navbar-default " role = " navigation " >  

    < div class = " container-fluid " >  

        < div class = " navbar-header " >  

            < button type = " button " class = " navbar-toggle " data-toggle = " collapse " data-target = " #example-navbar-collapse " >  

                < span class = " sr-only " > 切换导航 span >  

                < span class = " icon-bar " > span >  

                < span class = " icon-bar " > span >  

                < span class = " icon-bar " > span >  

             button >  

            < a class = " navbar-brand " href = " # " > 菜鸟教程 a >  

         div >  

        < div class = " collapse navbar-collapse " id = " example-navbar-collapse " >  

            < ul class = " nav navbar-nav " >  

                < li class = " active " > < a href = " # " > iOS a > li >  

                < li > < a href = " # " > SVN a > li >  

                < li class = " dropdown " >  

                    < a href = " # " class = " dropdown-toggle " data-toggle = " dropdown " > Java 

                        < b class = " caret " > b >  

                     a >  

                    < ul class = " dropdown-menu " >  

                        < li > < a href = " # " > jmeter a > li >  

                        < li > < a href = " # " > EJB a > li >  

                        < li > < a href = " # " > Jasper Report a > li >  

                        < li class = " divider " > li >  

                        < li > < a href = " # " > 分离的链接 a > li >  

                        < li class = " divider " > li >  

                        < li > < a href = " # " > 另一个分离的链接 a > li >  

                     ul >  

                 li >  

            ul >  

         div >  

     div >

nav >

尝试一下 »

结果如下所示：

导航栏中的表单

导航栏中的表单不是使用 Bootstrap 表单 中所讲到的默认的 class，它是使用 .navbar-form class。这确保了表单适当的垂直对齐和在较窄的视口中折叠的行为。使用对齐方式选项（这将在组件对齐方式部分进行详细讲解）来决定导航栏中的内容放置在哪里。

下面的实例演示了这点：

实例

< nav class = " navbar navbar-default " role = " navigation " >  

    < div class = " container-fluid " >  

        < div class = " navbar-header " >  

            < a class = " navbar-brand " href = " # " > 菜鸟教程 a >  

         div >  

        < form class = " navbar-form navbar-left " role = " search " >  

            < div class = " form-group " >  

                < input type = " text " class = " form-control " placeholder = " Search " >  

             div >  

            < button type = " submit " class = " btn btn-default " > 提交 button >  

         form >  

     div >

nav >

结果如下所示：

导航栏中的按钮

您可以使用 class .navbar-btn 向不在

中的 元素添加按钮，按钮在导航栏上垂直居中。.navbar-btn 可被使用在 和 元素上。

不要在  .navbar-nav 内的 元素上使用  .navbar-btn，因为它不是标准的  button class。

下面的实例演示了这点：

实例

< nav class = " navbar navbar-default " role = " navigation " >  

    < div class = " container-fluid " >  

        < div class = " navbar-header " >  

            < a class = " navbar-brand " href = " # " > 菜鸟教程 a >  

         div >  

        < div >  

            < form class = " navbar-form navbar-left " role = " search " >  

                < div class = " form-group " >  

                    < input type = " text " class = " form-control " placeholder = " Search " >  

                 div >  

                < button type = " submit " class = " btn btn-default " > 提交按钮 button >  

             form >  

            < button type = " button " class = " btn btn-default navbar-btn " > 导航栏按钮 button >  

         div >  

     div >

nav >

结果如下所示：

导航栏中的文本

如果需要在导航中包含文本字符串，请使用 class .navbar-text。这通常与

标签一起使用，确保适当的前导和颜色。下面的实例演示了这点：

实例

< nav class = " navbar navbar-default " role = " navigation " >  

    < div class = " container-fluid " >  

        < div class = " navbar-header " >  

            < a class = " navbar-brand " href = " # " > 菜鸟教程 a >  

         div >  

        < div >  

            < p class = " navbar-text " > Runoob 用户登录 p >  

         div >  

     div >

nav >

结果如下所示：

结合图标的导航链接

如果您想在常规的导航栏导航组件内使用图标，那么请使用 class glyphicon glyphicon-* 来设置图标，更多请查看 Bootstrap 图标 ，如下面的实例所示：

实例

< nav class = " navbar navbar-default " role = " navigation " >  

    < div class = " container-fluid " >  

        < div class = " navbar-header " >  

            < a class = " navbar-brand " href = " # " > 菜鸟教程 a >  

         div >  

        < ul class = " nav navbar-nav navbar-right " >  

            < li > < a href = " # " > < span class = " glyphicon glyphicon-user " > span > 注册 a > li >

            < li > < a href = " # " > < span class = " glyphicon glyphicon-log-in " > span > 登录 a > li >  

         ul >  

     div >  

nav >

结果如下所示：

组件对齐方式

您可以使用实用工具 class .navbar-left 或 .navbar-right 向左或向右对齐导航栏中的 导航链接、表单、按钮或文本 这些组件。这两个 class 都会在指定的方向上添加 CSS 浮动。下面的实例演示了这点：

实例

    

    

        菜鸟教程
    
    

        
        

            

                
                    Java
                    
                
                

                    
jmeter
                    
EJB
                    
Jasper Report
                    

                    
分离的链接
                    

                    
另一个分离的链接
                
            
        
        
            

向左对齐-提交按钮

向左对齐-文本

• Java
  • jmeter
  • EJB
  • Jasper Report
  • 分离的链接
  • 另一个分离的链接

向右对齐-提交按钮

向右对齐-文本

结果如下所示：

固定到顶部

Bootstrap 导航栏可以动态定位。默认情况下，它是块级元素，它是基于在 HTML 中放置的位置定位的。通过一些帮助器类，您可以把它放置在页面的顶部或者底部，或者您可以让它成为随着页面一起滚动的静态导航栏。

如果您想要让导航栏固定在页面的顶部，请向 .navbar class 添加 class .navbar-fixed-top。下面的实例演示了这点：

为了防止导航栏与页面主体中的其他内容的顶部相交错，请向 标签添加至少 50 像素的内边距（padding），内边距的值可以根据您的需要进行设置。

实例

< nav class = " navbar navbar-default navbar-fixed-top " role = " navigation " >  

    < div class = " container-fluid " >  

        < div class = " navbar-header " >  

            < a class = " navbar-brand " href = " # " > 菜鸟教程 a >  

         div >  

        < div >  

            < ul class = " nav navbar-nav " >  

                < li class = " active " > < a href = " # " > iOS a > li >  

                < li > < a href = " # " > SVN a > li >  

                < li class = " dropdown " >

                    < a href = " # " class = " dropdown-toggle " data-toggle = " dropdown " >                         Java 

                        < b class = " caret " > b >  

                     a >  

                    < ul class = " dropdown-menu " >  

                        < li > < a href = " # " > jmeter a > li >  

                        < li > < a href = " # " > EJB a > li >  

                        < li > < a href = " # " > Jasper Report a > li >  

                        < li class = " divider " > li >  

                        < li > < a href = " # " > 分离的链接 a > li >  

                        < li class = " divider " > li >  

                        < li > < a href = " # " > 另一个分离的链接 a > li >  

                     ul >  

                 li >  

             ul >  

         div >  

     div >

nav >

结果如下所示：

固定到底部

如果您想要让导航栏固定在页面的底部，请向 .navbar class 添加 class .navbar-fixed-bottom。下面的实例演示了这点：

实例

< nav class = " navbar navbar-default navbar-fixed-bottom " role = " navigation " >  

    < div class = " container-fluid " >  

        < div class = " navbar-header " >  

            < a class = " navbar-brand " href = " # " > 菜鸟教程 a >  

         div >  

        < div >  

            < ul class = " nav navbar-nav " >  

                < li class = " active " > < a href = " # " > iOS a > li >  

                < li > < a href = " # " > SVN a > li >  

                < li class = " dropdown " >  

                    < a href = " # " class = " dropdown-toggle " data-toggle = " dropdown " >

                        Java 

                        < b class = " caret " > b >  

                     a >  

                    < ul class = " dropdown-menu " >  

                        < li > < a href = " # " > jmeter a > li >  

                        < li > < a href = " # " > EJB a > li >  

                        < li > < a href = " # " > Jasper Report a > li >  

                        < li class = " divider " > li >  

                        < li > < a href = " # " > 分离的链接 a > li >  

                        < li class = " divider " > li >  

                        < li > < a href = " # " > 另一个分离的链接 a > li >  

                     ul >  

                  li >  

             ul >  

         div >  

     div >

nav >

结果如下所示：

静态的顶部

如需创建能随着页面一起滚动的导航栏，请添加 .navbar-static-top class。该 class 不要求向 添加内边距（padding）。

实例

< nav class = " navbar navbar-default navbar-static-top " role = " navigation " >  

< div class = " container-fluid " >  

        < div class = " navbar-header " >  

            < a class = " navbar-brand " href = " # " > 菜鸟教程 a >  

         div >  

        < div >  

            < ul class = " nav navbar-nav " >  

                < li class = " active " > < a href = " # " > iOS a > li >  

                < li > < a href = " # " > SVN a > li >  

                < li class = " dropdown " >  

                    < a href = " # " class = " dropdown-toggle " data-toggle = " dropdown " >

                        Java 

                        < b class = " caret " > b >  

                     a >  

                    < ul class = " dropdown-menu " >  

                        < li > < a href = " # " > jmeter a > li >  

                        < li > < a href = " # " > EJB a > li >  

                        < li > < a href = " # " > Jasper Report a > li >  

                        < li class = " divider " > li >  

                        < li > < a href = " # " > 分离的链接 a > li >  

                        < li class = " divider " > li >  

                        < li > < a href = " # " > 另一个分离的链接 a > li >  

                     ul >  

                  li >  

             ul >  

         div >  

     div >

nav >

结果如下所示：

反色的导航栏

为了创建一个带有黑色背景白色文本的反色的导航栏，只需要简单地向 .navbar class 添加 .navbar-inverse class 即可，如下面的实例所示：

为了防止导航栏与页面主体中的其他内容的顶部相交错，请向 标签添加至少 50 像素的内边距（padding），内边距的值可以根据您的需要进行设置。

实例

< nav class = " navbar navbar-inverse " role = " navigation " >

< div class = " container-fluid " >  

        < div class = " navbar-header " >  

            < a class = " navbar-brand " href = " # " > 菜鸟教程 a >  

         div >  

        < div >  

            < ul class = " nav navbar-nav " >  

                < li class = " active " > < a href = " # " > iOS a > li >  

                < li > < a href = " # " > SVN a > li >  

                < li class = " dropdown " >  

                    < a href = " # " class = " dropdown-toggle " data-toggle = " dropdown " >

                        Java 

                        < b class = " caret " > b >  

                     a >  

                    < ul class = " dropdown-menu " >  

                        < li > < a href = " # " > jmeter a > li >  

                        < li > < a href = " # " > EJB a > li >  

                        < li > < a href = " # " > Jasper Report a > li >  

                        < li class = " divider " > li >  

                        < li > < a href = " # " > 分离的链接 a > li >  

                        < li class = " divider " > li >  

                        < li > < a href = " # " > 另一个分离的链接 a > li >  

                     ul >  

                  li >  

             ul >  

         div >  

     div >

nav >

结果如下所示：