<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/2.2.4/jquery.min.js"></script>
<div class="container">
<div class="row">
<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<div class="container">
<h2 class="text-center">Bootstrap v4 · Layout Content Components Utilities · Examples</h2>
<div class="pos-f-t">
<nav class="navbar navbar-dark bg-dark">
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarToggleExternalContent" aria-controls="navbarToggleExternalContent" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<span class="navbar-text pl-3"><em><-- Navbar Component with Collapsed content toggleable via the navbar brand</em></span>
</nav>
<div class="collapse" id="navbarToggleExternalContent">
<div class="bg-dark p-4">
<div class="jumbotron">
<h1 class="display-4"><em>Jumbotron Component</em></h1>
<p class="lead">There are links on this page on GitHub and Blogspot.</p>
<hr class="my-4">
<div class="alert alert-danger alert-dismissible fade show" role="alert">
Press <strong>button</strong> below to show links in Modal window.
<button type="button" class="close" data-dismiss="alert" aria-label="Close">
<span aria-hidden="true">×</span>