Bootstrap 下拉菜單（Dropdowns） · W3School Bootstrap 教程

# Bootstrap 下拉菜單（Dropdowns）本章將重點介紹 Bootstrap 下拉菜單。下拉菜單是可切換的，是以列表格式顯示鏈接的上下文菜單。這可以通過與 [下拉菜單（Dropdown） JavaScript 插件](bootstrap-dropdown-plugin.html) 的互動來實現。如需使用下列菜單，只需要在 class **.dropdown** 內加上下拉菜單即可。下面的實例演示了基本的下拉菜單： ``` <!DOCTYPE html> <html> <head> <title>Bootstrap 實例 - 下拉菜單（Dropdowns）</title> <link href="/bootstrap/css/bootstrap.min.css" rel="stylesheet"> <script src="/scripts/jquery.min.js"></script> <script src="/bootstrap/js/bootstrap.min.js"></script> </head> <body> <div class="dropdown"> <button type="button" class="btn dropdown-toggle" id="dropdownMenu1" data-toggle="dropdown"> 主題 <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="#">數據挖掘</a> </li> <li role="presentation"> <a role="menuitem" tabindex="-1" href="#"> 數據通信/網絡 </a> </li> <li role="presentation" class="divider"></li> <li role="presentation"> <a role="menuitem" tabindex="-1" href="#">分離的鏈接</a> </li> </ul> </div> </body> </html> ``` [](/try/tryit.php?filename=bootstrap3-dropdown-basic) 結果如下所示： ![基本的下拉菜單（Dropdowns）](https://box.kancloud.cn/2015-12-18_5673d639e27a8.jpg) ## 選項 ### 對齊通過向 **.dropdown-menu** 添加 class **.pull-right** 來向右對齊下拉菜單。下面的實例演示了這點： ``` <!DOCTYPE html> <html> <head> <title>Bootstrap 實例 - 向右對齊下拉菜單</title> <link href="/bootstrap/css/bootstrap.min.css" rel="stylesheet"> <script src="/scripts/jquery.min.js"></script> <script src="/bootstrap/js/bootstrap.min.js"></script> </head> <body> <div class="dropdown"> <button type="button" class="btn dropdown-toggle" id="dropdownMenu1" data-toggle="dropdown">主題 <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="#">數據挖掘</a> </li> <li role="presentation"> <a role="menuitem" tabindex="-1" href="#"> 數據通信/網絡 </a> </li> <li role="presentation" class="divider"></li> <li role="presentation"> <a role="menuitem" tabindex="-1" href="#">分離的鏈接</a> </li> </ul> </div> </body> </html> ``` [](/try/tryit.php?filename=bootstrap3-dropdown-alignright) 結果如下所示： ![向右對齊下拉菜單](https://box.kancloud.cn/2015-12-18_5673d63a33036.jpg) ### 標題您可以使用 class **dropdown-header** 向下拉菜單的標簽區域添加標題。下面的實例演示了這點： ``` <!DOCTYPE html> <html> <head> <title>Bootstrap 實例 - 下拉菜單標題</title> <link href="/bootstrap/css/bootstrap.min.css" rel="stylesheet"> <script src="/scripts/jquery.min.js"></script> <script src="/bootstrap/js/bootstrap.min.js"></script> </head> <body> <div class="dropdown"> <button type="button" class="btn dropdown-toggle" id="dropdownMenu1" data-toggle="dropdown"> 主題 <span class="caret"></span> </button> <ul class="dropdown-menu" role="menu" aria-labelledby="dropdownMenu1"> <li role="presentation" class="dropdown-header">下拉菜單標題</li> <li role="presentation" > <a role="menuitem" tabindex="-1" href="#">Java</a> </li> <li role="presentation"> <a role="menuitem" tabindex="-1" href="#">數據挖掘</a> </li> <li role="presentation"> <a role="menuitem" tabindex="-1" href="#"> 數據通信/網絡 </a> </li> <li role="presentation" class="divider"></li> <li role="presentation" class="dropdown-header">下拉菜單標題</li> <li role="presentation"> <a role="menuitem" tabindex="-1" href="#">分離的鏈接</a> </li> </ul> </div> </body> </html> ``` [](/try/tryit.php?filename=bootstrap3-dropdown-header) 結果如下所示： ![下拉菜單標題](https://box.kancloud.cn/2015-12-18_5673d63a42b42.jpg)