HTML：
<div class="col-md-3">
<nav class="navbar">
<div class="container-fluid">
<div class="navbar-header common-border-bottom common-border-right common-border-left">
<button type="button" class="navbar-toggle collapsed" data-toggle="collapse"
data-target="#bs-example-navbar-collapse-1" aria-expanded="false">
<span class="sr-only"></span> <span class="icon-bar"></span> <span class="icon-bar"></span> <span class="icon-bar"></span>
</button>
</div>
<div class="collapse navbar-collapse common-border-right common-border-bottom common-border-left" id="bs-example-navbar-collapse-1">
<ul class="nav nav-stacked navbar-nav">
<li class="dropdown open input-interval">
<a class="dropdown-toggle" data-toggle="dropdown">人生无常<b class="caret"></b></a>
<ul class="dropdown-menu">
<li><a href="#">人性凉薄</a></li>
<li><a href="#">看透了然</a></li>
</ul>
</li>
</ul>
</div>
</div>
</nav>
</div>
由于加了open 所以默认是展开的，但是有个问题就是无论点击网页的任何地方都会折叠。以下的js解决了这个问题。
JS：
<script>
$(function () {
var openddt = $(".open").children('.dropdown-toggle');
openddt.attr('data-toggle', '');
openddt.click(function () {
$(this).siblings(".dropdown-menu").toggle();
});
})
</script>
转载于:https://www.cnblogs.com/Zmmy/p/8536554.html
相关资源：bootstrap树形下拉框 下拉框树形菜单
