Bootstrap 下拉菜单（Dropdowns）

本章将重点介绍 Bootstrap 下拉菜单。下拉菜单是可切换的，是以列表格式显示链接的上下文菜单。这可以通过与 下拉菜单（Dropdown） JavaScript 插件 的互动来实现。

如需使用下拉菜单，只需要在 class .dropdown 内加上下拉菜单即可。下面的实例演示了基本的下拉菜单：

<!DOCTYPE html>
<html>
<head>
   <title>Bootstrap 实例 - 下拉菜单（Dropdowns）</title>
   <link href="//cdn.bootcss.com/bootstrap/3.3.6/css/bootstrap.min.css" rel="external nofollow" target="_blank"  rel="external nofollow" target="_blank"  rel="external nofollow" target="_blank"  rel="stylesheet">
   <script src="//cdn.bootcss.com/jquery/2.1.1/jquery.min.js" rel="external nofollow"  rel="external nofollow"  rel="external nofollow" ></script>
   <script src="//cdn.bootcss.com/bootstrap/3.3.6/js/bootstrap.min.js" rel="external nofollow"  rel="external nofollow"  rel="external nofollow" ></script>
</head>
<body>

<div class="dropdown">
   <button type="button" class="btn dropdown-toggle" id="dropdownMenu1" 
      data-toggle="dropdown">
      主题
      <span class="caret"></span>
   </button>
   <ul class="dropdown-menu" role="menu" aria-labelledby="dropdownMenu1">
      <li role="presentation">
         <a role="menuitem" tabindex="-1" href="#">Java</a>
      </li>
      <li role="presentation">
         <a role="menuitem" tabindex="-1" href="#">数据挖掘</a>
      </li>
      <li role="presentation">
         <a role="menuitem" tabindex="-1" href="#">
            数据通信/网络
         </a>
      </li>
      <li role="presentation" class="divider"></li>
      <li role="presentation">
         <a role="menuitem" tabindex="-1" href="#">分离的链接</a>
      </li>
   </ul>
</div>


</body>
</html>

尝试一下 >>

结果如下所示：

基本的下拉菜单（Dropdowns）

选项

对齐

通过向 .dropdown-menu 添加 class .pull-right 来向右对齐下拉菜单。下面的实例演示了这点：

<!DOCTYPE html>
<html>
<head>
   <title>Bootstrap 实例 - 向右对齐下拉菜单</title>
   <link href="//cdn.bootcss.com/bootstrap/3.3.6/css/bootstrap.min.css" rel="external nofollow" target="_blank"  rel="external nofollow" target="_blank"  rel="external nofollow" target="_blank"  rel="stylesheet">
   <script src="//cdn.bootcss.com/jquery/2.1.1/jquery.min.js" rel="external nofollow"  rel="external nofollow"  rel="external nofollow" ></script>
   <script src="//cdn.bootcss.com/bootstrap/3.3.6/js/bootstrap.min.js" rel="external nofollow"  rel="external nofollow"  rel="external nofollow" ></script>
</head>
<body>

<div class="dropdown">
   <button type="button" class="btn dropdown-toggle" id="dropdownMenu1" 
      data-toggle="dropdown">主题
      <span class="caret"></span>
   </button>
   <ul class="dropdown-menu pull-right" role="menu" 
      aria-labelledby="dropdownMenu1">
      <li role="presentation">
         <a role="menuitem" tabindex="-1" href="#">Java</a>
      </li>
      <li role="presentation">
         <a role="menuitem" tabindex="-1" href="#">数据挖掘</a>
      </li>
      <li role="presentation">
         <a role="menuitem" tabindex="-1" href="#">
            数据通信/网络
         </a>
      </li>
      <li role="presentation" class="divider"></li>
      <li role="presentation">
         <a role="menuitem" tabindex="-1" href="#">分离的链接</a>
      </li>
   </ul>
</div>


</body>
</html>

尝试一下 >>

结果如下所示：

向右对齐下拉菜单

标题

您可以使用 class dropdown-header 向下拉菜单的标签区域添加标题。下面的实例演示了这点：

<!DOCTYPE html>
<html>
<head>
   <title>Bootstrap 实例 - 下拉菜单标题</title>
   <link href="//cdn.bootcss.com/bootstrap/3.3.6/css/bootstrap.min.css" rel="external nofollow" target="_blank"  rel="external nofollow" target="_blank"  rel="external nofollow" target="_blank"  rel="stylesheet">
   <script src="//cdn.bootcss.com/jquery/2.1.1/jquery.min.js" rel="external nofollow"  rel="external nofollow"  rel="external nofollow" ></script>
   <script src="//cdn.bootcss.com/bootstrap/3.3.6/js/bootstrap.min.js" rel="external nofollow"  rel="external nofollow"  rel="external nofollow" ></script>
</head>
<body>

<div class="dropdown">
   <button type="button" class="btn dropdown-toggle" id="dropdownMenu1" 
      data-toggle="dropdown">
      主题
      <span class="caret"></span>
   </button>
   <ul class="dropdown-menu" role="menu" aria-labelledby="dropdownMenu1">
      <li role="presentation" class="dropdown-header">下拉菜单标题</li>
      <li role="presentation" >
         <a role="menuitem" tabindex="-1" href="#">Java</a>
      </li>
      <li role="presentation">
         <a role="menuitem" tabindex="-1" href="#">数据挖掘</a>
      </li>
      <li role="presentation">
         <a role="menuitem" tabindex="-1" href="#">
            数据通信/网络
         </a>
      </li>
      <li role="presentation" class="divider"></li>
      <li role="presentation" class="dropdown-header">下拉菜单标题</li>
      <li role="presentation">
         <a role="menuitem" tabindex="-1" href="#">分离的链接</a>
      </li>
   </ul>
</div>


</body>
</html>

尝试一下 >>

结果如下所示：

下拉菜单标题