<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>
<!------ Include the above in your HEAD tag ---------->
<div class="container">
<div class="row">
<div class="alert alert-success">
<strong>Success!</strong> Indicates a successful or positive action.
</div>
<div class="alert alert-info">
<strong>Info!</strong> Indicates a neutral informative change or action.
</div>
<div class="alert alert-warning">
<strong>Warning!</strong> Indicates a warning that might need attention.
</div>
<div class="alert alert-danger">
<strong>Danger!</strong> Indicates a dangerous or potentially negative action.
</div>
</div>
</div>