bootstrap 多级导航 PC 手机解决方案
多于两层的导航比较少，这里业务需要 bootstrap 的多级导航。在 PC 上悬停时出现子菜单（默认是 click 的方式），在手机上依然是 click 出现子菜单，不能是悬停。PC 上下拉选项可以点击进入链接，手机点击显示或隐藏子菜单。
以下是 demo
在线 demo
<html>
<head>
<!-- 最新版本的 Bootstrap 核心 CSS 文件 -->
<link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">
<script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.js"></script>
<!-- 最新的 Bootstrap 核心 JavaScript 文件 -->
<script src="https://cdn.bootcss.com/bootstrap/3.3.7/js/bootstrap.min.js" integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa" crossorigin="anonymous"></script>
</head>
<style>
@media (min-width: 767px) {
.navbar-nav .dropdown-menu .caret {
transform: rotate(-90deg);
}
}
</style>
</head>
<body>
<div class="navbar navbar-default navbar-fixed-top" role="navigation">
<div class="container">
<div class="navbar-header">
<button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-collapse">
<span class="sr-only">Toggle navigation</span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<a class="navbar-brand" href="#">NavBar</a>
</div>
<div class="collapse navbar-collapse">
<ul class="nav navbar-nav">
<li class="active"><a href="#">Home</a></li>
<li><a href="https://github.com/fontenele/bootstrap-navbar-dropdowns" target="_blank">GitHub</a></li>
<li>
<a href="#" class="dropdown-toggle" data-toggle="dropdown">Menu 1 <b class="caret"></b></a>
<ul class="dropdown-menu">
<li><a href="#">Action [Menu 1.1]</a></li>
<li><a href="#">Another action [Menu 1.1]</a></li>
<li><a href="#">Something else here [Menu 1.1]</a></li>
<li class="divider"></li>
<li><a href="#">Separated link [Menu 1.1]</a></li>
<li class="divider"></li>
<li><a href="#">One more separated link [Menu 1.1]</a></li>
<li>
<a href="#" class="dropdown-toggle" data-toggle="dropdown">Dropdown [Menu 1.1] <b class="caret"></b></a>
<ul class="dropdown-menu">
<li><a href="#">Action [Menu 1.2]</a></li>
<li>
<a href="#" class="dropdown-toggle" data-toggle="dropdown">Dropdown [Menu 1.2] <b class="caret"></b></a>
<ul class="dropdown-menu">
<li>
<a href="#" class="dropdown-toggle" data-toggle="dropdown">Dropdown [Menu 1.3] <b class="caret"></b></a>
<ul class="dropdown-menu">
<li><a href="#">Action [Menu 1.4]</a></li>
<li><a href="#">Another action [Menu 1.4]</a></li>
<li><a href="#">Something else here [Menu 1.4]</a></li>
<li class="divider"></li>
<li><a href="#">Separated link [Menu 1.4]</a></li>
<li class="divider"></li>
<li><a href="#">One more separated link [Menu 1.4]</a></li>
</ul>
</li>
</ul>
</li>
</ul>
</li>
</ul>
</li>
<li>
<a href="#" class="dropdown-toggle" data-toggle="dropdown">Menu 2 <b class="caret"></b></a>
<ul class="dropdown-menu">
<li><a href="#">Action [Menu 2.1]</a></li>
<li><a href="#">Another action [Menu 2.1]</a></li>
<li><a href="#">Something else here [Menu 2.1]</a></li>
<li class="divider"></li>
<li><a href="#">Separated link [Menu 2.1]</a></li>
<li class="divider"></li>
<li><a href="#">One more separated link [Menu 2.1]</a></li>
<li>
<a href="#" class="dropdown-toggle" data-toggle="dropdown">Dropdown [Menu 2.1] <b class="caret"></b></a>
<ul class="dropdown-menu">
<li><a href="#">Action [Menu 2.2]</a></li>
<li><a href="#">Another action [Menu 2.2]</a></li>
<li><a href="#">Something else here [Menu 2.2]</a></li>
<li class="divider"></li>
<li><a href="#">Separated link [Menu 2.2]</a></li>
<li class="divider"></li>
<li>
<a href="#" class="dropdown-toggle" data-toggle="dropdown">Dropdown [Menu 2.2] <b class="caret"></b></a>
<ul class="dropdown-menu">
<li>
<a href="#" class="dropdown-toggle" data-toggle="dropdown">Dropdown [Menu 2.3] <b class="caret"></b></a>
<ul class="dropdown-menu">
<li><a href="#">Action [Menu 2.4]</a></li>
<li><a href="#">Another action [Menu 2.4]</a></li>
<li><a href="#">Something else here [Menu 2.4]</a></li>
<li class="divider"></li>
<li><a href="#">Separated link [Menu 2.4]</a></li>
<li class="divider"></li>
<li><a href="#">One more separated link [Menu 2.4]</a></li>
</ul>
</li>
</ul>
</li>
</ul>
</li>
</ul>
</li>
</ul>
</div>
<!--/.nav-collapse -->
</div>
</div>
<script type="text/javascript">
jQuery(document).ready(function() {
var $ = jQuery;
function dropdownOpen() {
// console.log('drop');
var screenWidth = $(window).width();
var isPhone = screenWidth < 768;
if (!isPhone) {
$('.navbar-nav a.dropdown-toggle').unbind('mouseover').on('mouseover', function() {
// console.log(this);
var $el = $(this);
var $parent = $(this).offsetParent(".dropdown-menu");
$(this).parent("li").addClass('open');
if (!$parent.parent().hasClass('nav')) {
$el.next().css({
"top": $el[0].offsetTop,
"left": $parent.outerWidth() - 4
});
}
$('.nav li.open').not($(this).parents("li")).removeClass("open");
return false;
});
$('.navbar-nav a.dropdown-toggle').addClass('disabled');
$('.navbar-nav a.dropdown-toggle').unbind('click');
} else {
$('.navbar-nav a.dropdown-toggle').unbind('mouseover');
$('.navbar-nav a.dropdown-toggle').removeClass('disabled');
$('.navbar-nav a.dropdown-toggle').unbind('click').on('click', function() {
$(this).parent("li").toggleClass('open');
return false;
});
}
}
// resize 会执行两次
$(window).on('resize', dropdownOpen).trigger('resize');
});
</script>
</body>
</html>
