Layui实现三级导航菜单的完整代码示例

<!DOCTYPE html>
<html>
<head>
 <meta charset="utf-8">
 <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1">
 <title>layout 后台大布局 - Layui</title>
 <link rel="stylesheet" href="../css/layui.css" rel="external nofollow" >
 <script src="../layui.js"></script>
 <style>
 .layui-layout-left{position: absolute !important; left: 0px; top: 0;}
 /*layui child nav*/
 .layui-nav-child{display: none; position: absolute; left: 0; top: 65px; min-width: 100%; line-height: 36px; padding: 5px 0; box-shadow: 0 2px 4px rgba(0,0,0,.12); border: 1px solid #d2d2d2; background-color: #fff; z-index: 100; border-radius: 2px; white-space: nowrap;}
 .layui-nav .layui-nav-child a{color: white;}
 .layui-nav .layui-nav-child a:hover{background-color:deepskyblue; color: white;}
 .layui-nav-child dd{position: relative;}
 .layui-nav-child dd.layui-this{background-color: transparent; color: white;}
 .layui-nav .layui-nav-child dd.layui-this a{background-color: transparent; color: white;}
 .layui-nav-child dd.layui-this:after{display: none;}
 /*layui third level nav*/
 .layui-nav-third-child{display: none; position: absolute; left: 105px;top:25px;min-width: 100%; line-height: 36px; padding: 5px 0; box-shadow: 0 2px 4px rgba(0,0,0,.12); border: 1px solid #d2d2d2; background-color: #fff; z-index: 100; border-radius: 2px; white-space: nowrap;}
 .layui-nav .layui-nav-third-child a{color: white;}
 .layui-nav .layui-nav-third-child a:hover{background-color:deepskyblue; color: white;}
 .layui-nav-third-child li{position: relative;}
 .layui-nav-third-child li{background-color: transparent; color: white;}
 .layui-nav .layui-nav-third-child li.layui-this a{background-color: transparent; color: white;}
 .layui-nav-third-child li:after{display: none;}
 </style>
</head>
<body class="layui-layout-body ">
<div class="layui-layout layui-layout-admin layui-bg-blue">

 <div class="layui-header layui-bg-blue">
  <div style="margin-left: 20px">
  <b style="font-size: 35px">船信保密安全综合管控平台</b><br>
  <b>CSIT integrated Control System of Confidentiality and Security</b>

  </div>
 <!-- 头部区域（可配合layui已有的水平导航） -->

 <ul class="layui-nav layui-layout-right">
  <li class="layui-nav-item">
  <a href="javascript:;" >
   <img src="http://t.cn/RCzsdCq" class="layui-nav-img">
   贤心
  </a>
  <dl class="layui-nav-child">
   <dd><a href="#" >基本资料</a></dd>
   <dd><a href="#" >安全设置</a></dd>
  </dl>
  </li>
  <li class="layui-nav-item"><a href="">退了</a></li>
 </ul>
 </div>
 <div class="layui-header layui-bg-blue">
 <!-- 头部区域（可配合layui已有的水平导航） -->
 <ul class="layui-nav layui-layout-left">
  <li class="layui-nav-item"><a href="#" >控制台</a></li>
  <li class="layui-nav-item"><a href="#" >商品管理</a></li>
  <li class="layui-nav-item"><a href="#" >用户</a></li>
  <li class="layui-nav-item">
  <a href="javascript:;" >其它系统</a>
  <dl class="layui-nav-child layui-bg-blue">
   <dd><a href="">邮件管理</a></dd>
   <dd><a href="">消息管理</a></dd>
   <dd><a href="">授权管理</a></dd>
   <dd>
   <a href="javascript:;" class="third-class">其它系统2</a>
   <ol class="layui-nav-third-child layui-bg-blue">
    <li><a href="">邮件管理2</a></li>
    <li><a href="">消息管理2</a></li>
    <li><a href="">授权管理2</a></li>
   </ol>
   </dd>
   <dd>
   <a href="javascript:;" class="third-class">其它系统3</a>
   <ol class="layui-nav-third-child layui-bg-blue">
    <li><a href="">邮件管理3</a></li>
    <li><a href="">消息管理3</a></li>
    <li><a href="">授权管理3</a></li>
   </ol>
   </dd>

  </dl>
  </li>
 </ul>
 </div>
 <div class="layui-body">
 <!-- 内容主体区域 -->
 <div style="padding: 15px;">内容主体区域</div>
 </div>

 <div class="layui-footer">
 <!-- 底部固定区域 -->
 © layui.com - 底部固定区域
 </div>
</div>
<script>
//JavaScript代码区域
 layui.use(['element','jquery'], function(){
 var element = layui.element,$=layui.jquery;
 $(".layui-nav-third-child").hide();
 $(".third-class").on('click',function () {
  $(".layui-nav-third-child").hide();
  $(this).next().show();
 });
 });
</script>
</body>
</html>