以下代码中,按钮在lg
和xl
上应该是隐藏的;而折叠内容仅在md
上可切换,或者是从md
向下可切换到xs
吗?有人能帮忙解释一下吗?
<nav class="navbar navbar-light bg-faded">
<button class="navbar-toggler hidden-lg-up" type="button" data-toggle="collapse" data-target="#exCollapsingNavbar2">
☰
</button>
<div class="collapse navbar-toggleable-md" id="exCollapsingNavbar2">
<a class="navbar-brand" href="#">Responsive navbar</a>
<ul class="nav navbar-nav">
<li class="nav-item active">
<a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Features</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Pricing</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">About</a>
</li>
</ul>
</div>
</nav>