Bootstrap 虽好，但对于复杂的界面，还是有N多组件需要自己扩展，并且要往简洁、大气的Bootstrap界面上靠，着实要费一些功夫。下面分享一个Bootstrap 3的多级下拉菜单，无需第三方Js脚本，复制后直接可用。
Bootstrap 3 的多级下拉菜单示例
<!DOCTYPE HTML> <html lang="zh-CN"> <head> <meta charset="UTF-8"> <title>Bootstrap 3 的多级下拉菜单示例</title> <script type="text/javascript" src="http://libs.baidu.com/jquery/1.9.0/jquery.js"></script> <link rel="stylesheet" href="http://libs.baidu.com/bootstrap/3.0.3/css/bootstrap.min.css"/> <script type="text/javascript" src="http://libs.baidu.com/bootstrap/3.0.3/js/bootstrap.min.js"></script> <style type="text/css"> .dropdown-submenu { position: relative; } .dropdown-submenu > .dropdown-menu { top: 0; left: 100%; margin-top: -6px; margin-left: -1px; -webkit-border-radius: 0 6px 6px 6px; -moz-border-radius: 0 6px 6px; border-radius: 0 6px 6px 6px; } .dropdown-submenu:hover > .dropdown-menu { display: block; } .dropdown-submenu > a:after { display: block; content: " "; float: right; width: 0; height: 0; border-color: transparent; border-style: solid; border-width: 5px 0 5px 5px; border-left-color: #ccc; margin-top: 5px; margin-right: -10px; } .dropdown-submenu:hover > a:after { border-left-color: #fff; } .dropdown-submenu.pull-left { float: none; } .dropdown-submenu.pull-left > .dropdown-menu { left: -100%; margin-left: 10px; -webkit-border-radius: 6px 0 6px 6px; -moz-border-radius: 6px 0 6px 6px; border-radius: 6px 0 6px 6px; } </style> </head> <body> <div class="container"> <div class="row"> <h2>Bootstrap 3多级下拉菜单</h2> <hr> <div class="dropdown"> <a id="dLabel" role="button" data-toggle="dropdown" class="btn btn-primary" data-target="#" href="javascript:;"> 下拉多级菜单 <span class="caret"></span> </a> <ul class="dropdown-menu multi-level" role="menu" aria-labelledby="dropdownMenu"> <li><a href="javascript:;">一级菜单</a></li> <li><a href="javascript:;">一级菜单</a></li> <li class="divider"></li> <li class="dropdown-submenu"> <a tabindex="-1" href="javascript:;">一级菜单</a> <ul class="dropdown-menu"> <li><a tabindex="-1" href="javascript:;">二级菜单</a></li> <li class="divider"></li> <li class="dropdown-submenu"> <a href="javascript:;">二级菜单</a> <ul class="dropdown-menu"> <li><a href="javascript:;">三级菜单</a></li> </ul> </li> </ul> </li> </ul> </div> </div> </div> </body> </html>
Bootstrap 4 多级下拉菜单示例
<!DOCTYPE html> <html lang="en"> <head> <!-- Required meta tags --> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no"> <title>Page Title</title> <!-- Bootstrap CSS --> <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" crossorigin="anonymous"> <style type="text/css"> .dropdown-submenu { position: relative; } .dropdown-submenu > .dropdown-menu { top: 0; left: 100%; margin-top: -6px; margin-left: -1px; -webkit-border-radius: 0 6px 6px 6px; -moz-border-radius: 0 6px 6px; border-radius: 0 6px 6px 6px; } .dropdown-submenu:hover > .dropdown-menu { display: block; } .dropdown-submenu > a:after { display: block; content: " "; float: right; width: 0; height: 0; border-color: transparent; border-style: solid; border-width: 5px 0 5px 5px; border-left-color: #ccc; margin-top: 5px; margin-right: -10px; } .dropdown-submenu:hover > a:after { /*border-left-color: #fff;*/ } .dropdown-submenu.pull-left { float: none; } .dropdown-submenu.pull-left > .dropdown-menu { left: -100%; margin-left: 10px; -webkit-border-radius: 6px 0 6px 6px; -moz-border-radius: 6px 0 6px 6px; border-radius: 6px 0 6px 6px; } </style> </head> <body> <div class="dropdown open"> <button class="btn btn-primary dropdown-toggle" type="button" id="dropdownMenu1" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false"> Dropdown </button> <div class="dropdown-menu" aria-labelledby="dropdownMenu1"> <div class="dropdown-submenu"> <a class="dropdown-item" tabindex="-1" href="javascript:;">一级菜单</a> <div class="dropdown-menu dropdown-" aria-labelledby="dropdownMenu2"> <a class="dropdown-item" href="#">Action</a> <a class="dropdown-item" href="#">Action</a> <a class="dropdown-item" href="#">Action</a> </div> </div> <div class="dropdown-divider"></div> <a class="dropdown-item" href="#">Action</a> <a class="dropdown-item" href="#">Action</a> <a class="dropdown-item" href="#">Action</a> </div> </div> <!-- Optional JavaScript --> <!-- jQuery first, then Popper.js, then Bootstrap JS --> <script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" crossorigin="anonymous"></script> <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.11.0/umd/popper.min.js" crossorigin="anonymous"></script> <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js" crossorigin="anonymous"></script> </body> </html>
原文链接：http://blog.csdn.net/zhongyuan_1990/article/details/31789541