我是网络开发和 HTML 的新手。你能告诉我为什么当屏幕调整为较小的屏幕时，我的导航栏菜单项没有出现在折叠的导航菜单中。
右侧折叠的导航菜单缺少菜单项。使用 Bootstrap 3
<html>
<head>
<meta charset="UTF-8">
<title>My First Web App</title>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">
<link href="https://fonts.googleapis.com/css?family=Fjalla+One" rel="stylesheet">
</head>
<body>
<nav class = "navbar navbar-inverse" >
<div class = "container-fluid">
<div class = "navbar-header">
<button type="button" class = "navbar-toggle" data-toggle = "collapse" data-target = "topNavBar">
<span class = "icon-bar" ></span>
<span class = "icon-bar" ></span>
<span class = "icon-bar" ></span>
</button>
<a class="navbar-brand" href="#"><span class="glyphicon glyphicon-home" aria-hidden="true"></span> Home</a>
</div>
<div class="collapse navbar-collapse" id="topNavBar">
<!-- Collapsed menu itemsItems -->
<ul class="nav navbar-nav">
<li><a href="#"><span aria-hidden="true"></span> Python</a></li>
<li><a href="#"><span aria-hidden="true"></span> Java</a></li>
<li><a href="#"><span aria-hidden="true"></span> C++</a></li>
<li><a href="#"><span class="glyphicon glyphicon-envelope" aria-hidden="true"></span> Mail</a></li>
</ul>
<ul class="nav navbar-nav navbar-right">
<li>
<a href="#">
<span class="glyphicon glyphicon-user" aria-hidden="true"></span> Me
</a>
</li>
<li>
<a href="#">
<span class="glyphicon glyphicon-off" aria-hidden="true"></span> Logout
</a>
</li>
</ul>
</div>
</div>
</nav>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js" integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa" crossorigin="anonymous"></script>
</body>
</html>
最佳答案
<html>
<head>
<meta charset="UTF-8">
<title>My First Web App</title>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">
<link href="https://fonts.googleapis.com/css?family=Fjalla+One" rel="stylesheet">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
</head>
<body>
<nav class = "navbar navbar-inverse" >
<div class = "container-fluid">
<div class = "navbar-header">
<button type="button" class = "navbar-toggle" data-toggle = "collapse" data-target = "#topNavBar"> <!--here-->
<span class = "icon-bar" ></span>
<span class = "icon-bar" ></span>
<span class = "icon-bar" ></span>
</button>
<a class="navbar-brand" href="#"><span class="glyphicon glyphicon-home" aria-hidden="true"></span> Home</a>
</div>
<div class="collapse navbar-collapse" id="topNavBar">
<!-- Collapsed menu itemsItems -->
<ul class="nav navbar-nav">
<li><a href="#"><span aria-hidden="true"></span> Python</a></li>
<li><a href="#"><span aria-hidden="true"></span> Java</a></li>
<li><a href="#"><span aria-hidden="true"></span> C++</a></li>
<li><a href="#"><span class="glyphicon glyphicon-envelope" aria-hidden="true"></span> Mail</a></li>
</ul>
<ul class="nav navbar-nav navbar-right">
<li>
<a href="#">
<span class="glyphicon glyphicon-user" aria-hidden="true"></span> Me
</a>
</li>
<li>
<a href="#">
<span class="glyphicon glyphicon-off" aria-hidden="true"></span> Logout
</a>
</li>
</ul>
</div>
</div>
</nav>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js" integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa" crossorigin="anonymous"></script>
</body>
</html>关于javascript - HTML - 折叠的导航菜单不显示菜单项，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/48553241/