详解bootstrap导航栏.nav与.navbar区别

刚刚看了bootstrap的导航栏，发现有点弄混了，现在来整理一下；

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。

一、简单的ul,li组成的导航：

<ul class="nav nav-pills justify-content-center bg-dark nav-dark">
   <li class="nav-item">
     <a 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" 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" rel="external nofollow" rel="external nofollow" class="nav-link">1</a>
   </li>
   <li class="nav-item">
     <a 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" 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" rel="external nofollow" rel="external nofollow" class="nav-link">2</a>
   </li>
   <li class="nav-item">
     <a 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" 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" rel="external nofollow" rel="external nofollow" class="nav-link">3</a>
   </li>
 </ul>

//解析：.nav .nav-item .nav-link表示ul li是导航——.nav-pills表示胶囊状导航——.bg-dark/.nav-dark表示黑底白字——.justify-content-center表示导航栏在浏览器上居中显示

在浏览器上显示为：

缩小浏览器窗口显示为：

二、导航栏——<nav>标签中class="navbar navbar-expand-sm"——<ul>中class="navbar-nav"——<li>中class="nav-item"

代码为：

<nav class="navbar navbar-expand-sm bg-dark navbar-dark">
 <ul class="navbar-nav">
   <li class="nav-item active">
     <a 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" 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" rel="external nofollow" rel="external nofollow" class="nav-link">link1</a>
   </li>
   <li class="nav-item">
     <a 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" 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" rel="external nofollow" rel="external nofollow" class="nav-link">link1</a>
   </li>
   <li class="nav-item">
     <a 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" 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" rel="external nofollow" rel="external nofollow" class="nav-link">link1</a>
   </li>
   <li class="nav-item">
     <a 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" 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" rel="external nofollow" rel="external nofollow" class="nav-link">link1</a>
   </li>  
 </ul>
</nav>

正常窗口显示为：

 缩小窗口小于576px时： 

三、折叠导航栏

当窗口小于576px的时候，不仅仅是简单的编程垂直导航；显示为一个button按钮，导航链接隐藏，点击button显示；

 代码为：

<nav class="navbar navbar-expand-sm bg-dark navbar-dark fixed-top">
 <a 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" 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" rel="external nofollow" rel="external nofollow" class="navbar-brand">
     <img src="" alt="logo" style="width:70px;height:30px;">
 </a>
 <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#collapsible">
   <span class="navbar-toggler-icon"></span>
 </button>
 <div class="collapse navbar-collapse" id="collapsible">
 <ul class="navbar-nav">
   <li class="nav-item active">
     <a 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" 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" rel="external nofollow" rel="external nofollow" class="nav-link">link1</a>
   </li>
   <li class="nav-item">
     <a 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" 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" rel="external nofollow" rel="external nofollow" class="nav-link">link1</a>
   </li>
   <li class="nav-item">
     <a 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" 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" rel="external nofollow" rel="external nofollow" class="nav-link">link1</a>
   </li>
   <li class="nav-item">
     <a 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" 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" rel="external nofollow" rel="external nofollow" class="nav-link">link1</a>
   </li>  
 </ul>

</nav>

 //注意：.navbar-brand是品牌logo；

窗口大于576的时候，显示为：

窗口小于576的时候，显示为：

四、导航栏加上form表单表示搜索框：【？？？？？】

代码如下：

<nav class="navbar navbar-expand-sm bg-dark navbar-dark fixed-top">
 <a 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" 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" rel="external nofollow" rel="external nofollow" class="navbar-brand">
     <img src="" alt="logo" style="width:70px;height:30px;">
 </a>
 <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#collapsible">
   <span class="navbar-toggler-icon"></span>
 </button>
 <div class="collapse navbar-collapse" id="collapsible">
 <ul class="navbar-nav">
   <li class="nav-item active">
     <a 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" 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" rel="external nofollow" rel="external nofollow" class="nav-link">link1</a>
   </li>
   <li class="nav-item">
     <a 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" 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" rel="external nofollow" rel="external nofollow" class="nav-link">link1</a>
   </li>
   <li class="nav-item">
     <a 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" 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" rel="external nofollow" rel="external nofollow" class="nav-link">link1</a>
   </li>
   <li class="nav-item">
     <a 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" 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" rel="external nofollow" rel="external nofollow" class="nav-link">link1</a>
   </li>  
 </ul>
 <form class="form-inline">
       <div class="input-group">
         <span class="input-group-addon">@</span>
         <input list="dl" type="text" class="form-control" placeholder="Search"/>
         <datalist id="dl">
           <option value="IE"></option>
           <option value="Firefox"></option>
           <option value="chrome"></option>
           <option value="safari"></option>
         </datalist>
       </div>

<button class="btn btn-success" type="submit">search</button>
     </form>
</nav>

如图所示，如何使得导航栏中的form表单右对齐，移到最右边？？？？？float：eight应该也行吧。。

emmmm.....知道了上面的解决方法了：利用网格系统，将左边的ul,li和右边的form表单分别排列；.col-sm-6;然后再给form表单右浮动；

代码如下：

<div class="container-fluid">
 <div class="row">
   <!-- 导航栏 -->
   <nav class="navbar fixed-top navbar-expand-sm bg-dark navbar-dark">
     <div class="col-lg-4">
     <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" 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" rel="external nofollow" rel="external nofollow" >link1</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" 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" rel="external nofollow" rel="external nofollow" >link2</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" 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" rel="external nofollow" rel="external nofollow" >link3</a>
       </li>
     </ul>
     </div>
<!-- 导航栏表单与按钮 -->
   <div class="col-lg-8">
     <form class="form-inline" style="float:right;">
       <div class="input-group">
         <span class="input-group-addon">@</span>
         <input list="dl" type="text" class="form-control" placeholder="Search"/>
         <datalist id="dl">
           <option value="IE"></option>
           <option value="Firefox"></option>
           <option value="chrome"></option>
           <option value="safari"></option>
         </datalist>
         <button class="btn btn-success" type="submit">search</button>
       </div>              
     </form>
     </div>      
   </nav>
   </div>
     </div>

来源：http://www.cnblogs.com/Zhang-jin/p/7881694.html