这是一款基于bootsnav的简洁多级导航菜单。bootsnav是以bootstrap为基础的导航菜单插件。被多级导航菜单效果是在bootsnav的基础上，对菜单样式进行了一些美化加工。
在页面中引入bootstrap相关文件，jquery库jquery.min.js和bootstrap框架文件bootstrap.min.css，bootstrap.min.js。
font-awesome.min.css字体图标样式文件，bootsnav.js导航脚本文件
<link href="path/to/bootstrap.min.css" rel="stylesheet">
<link href="path/to/font-awesome.min.css" rel="stylesheet">
<link rel="stylesheet" type="text/css" href="css/bootsnav.css">
<script type="text/javascript" src="path/to/jquery.min.js"></script>
<script src="path/to/bootstrap.min.js"></script>
<script type="text/javascript" src="path/to/bootsnav.js"></script>
该多级导航菜单的基本HTML结构如下：
<div class="container">
<div class="row">
<div class="col-md-12">
<nav class="navbar navbar-default navbar-mobile bootsnav on">
<div class="navbar-header">
<button type="button" class="navbar-toggle" data-toggle="collapse" data-target="#navbar-menu">
<i class="fa fa-bars"></i>
</button>
</div>
<div class="collapse navbar-collapse" id="navbar-menu">
<ul class="nav navbar-nav" data-in="fadeInDown" data-out="fadeOutUp">
<li><a href="#">Home</a></li>
<li><a href="#">About Us</a></li>
<li class="dropdown">
<a href="#" class="dropdown-toggle" data-toggle="dropdown">Shortcodes</a>
<ul class="dropdown-menu animated">
<li><a href="#">Custom Menu</a></li>
<li><a href="#">Custom Menu</a></li>
<li class="dropdown">
<a href="#" class="dropdown-toggle" data-toggle="dropdown">Sub Menu</a>
<ul class="dropdown-menu animated">
<li><a href="#">Custom Menu</a></li>
<li><a href="#">Custom Menu</a></li>
<li class="dropdown">
<a href="#" class="dropdown-toggle" data-toggle="dropdown">Sub Menu</a>
<ul class="dropdown-menu multi-dropdown animated">
<li><a href="#">Custom Menu</a></li>
<li><a href="#">Custom Menu</a></li>
<li><a href="#">Custom Menu</a></li>
<li><a href="#">Custom Menu</a></li>
</ul>
</li>
<li><a href="#">Custom Menu</a></li>
</ul>
</li>
<li><a href="#">Custom Menu</a></li>
<li><a href="#">Custom Menu</a></li>
<li><a href="#">Custom Menu</a></li>
<li><a href="#">Custom Menu</a></li>
</ul>
</li>
<li class="dropdown">
<a href="#" class="dropdown-toggle" data-toggle="dropdown">Pages</a>
<ul class="dropdown-menu animated">
<li><a href="#">Custom Menu</a></li>
<li><a href="#">Custom Menu</a></li>
<li class="dropdown">
<a href="#" class="dropdown-toggle" data-toggle="dropdown">Sub Menu</a>
<ul class="dropdown-menu animated">
<li><a href="#">Custom Menu</a></li>
<li><a href="#">Custom Menu</a></li>
<li class="dropdown">
<a href="#" class="dropdown-toggle" data-toggle="dropdown">Sub Menu</a>
<ul class="dropdown-menu multi-dropdown animated">
<li><a href="#">Custom Menu</a></li>
<li><a href="#">Custom Menu</a></li>
<li><a href="#">Custom Menu</a></li>
<li><a href="#">Custom Menu</a></li>
</ul>
</li>
<li><a href="#">Custom Menu</a></li>
</ul>
</li>
<li><a href="#">Custom Menu</a></li>
<li><a href="#">Custom Menu</a></li>
<li><a href="#">Custom Menu</a></li>
<li><a href="#">Custom Menu</a></li>
</ul>
</li>
<li><a href="#">Portfolio</a></li>
<li><a href="#">Contact Us</a></li>
</ul>
</div>
</nav>
</div>
</div>
</div>
使用下面的CSS代码来对多级导航菜单进行美化。
.navbar-brand{
padding: 29px 15px;
height: auto;
}
nav.navbar.bootsnav{
border: none;
margin-bottom: 150px;
}
.navbar-nav{
float: left;
}
nav.navbar.bootsnav ul.nav > li > a{
color: #474747;
text-transform: uppercase;
padding: 30px;
}
nav.navbar.bootsnav ul.nav > li:hover{
background: #f4f4f4;
}
.nav > li:after{
content: "";
width: 0;
height: 5px;
background: #34c9dd;
position: absolute;
bottom: 0;
left: 0;
transition: all 0.5s ease 0s;
}
.nav > li:hover:after{
width: 100%;
}
nav.navbar.bootsnav ul.nav > li.dropdown > a.dropdown-toggle:after{
content: "+";
font-family: 'FontAwesome';
font-size: 16px;
font-weight: 500;
position: absolute;
top: 35%;
right: 10%;
transition: all 0.4s ease 0s;
}
nav.navbar.bootsnav ul.nav > li.dropdown.on > a.dropdown-toggle:after{
content: "\f105";
transform: rotate(90deg);
}
.dropdown-menu.multi-dropdown{
position: absolute;
left: -100% !important;
}
nav.navbar.bootsnav li.dropdown ul.dropdown-menu{
box-shadow: 0 0 10px rgba(0, 0, 0, 0.3);
border: none;
}
@media only screen and (max-width:990px){
nav.navbar.bootsnav ul.nav > li.dropdown > a.dropdown-toggle:after,
nav.navbar.bootsnav ul.nav > li.dropdown.on > a.dropdown-toggle:after{ content: " "; }
.dropdown-menu.multi-dropdown{ left: 0 !important; }
nav.navbar.bootsnav ul.nav > li:hover{ background: transparent; }
nav.navbar.bootsnav ul.nav > li > a{ margin: 0; }
}
将以上代码添加到您的文件中，即可实现网站导航效果。