bootstrap_alert.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css" integrity="sha384-Vkoo8x4CGsO3+Hhxv8T/Q5PaXtkKtu6ug5TOeNV6gBiFeWPGFN9MuhOf23Q9Ifjh" crossorigin="anonymous">
    <title>Bootstrap alert</title>
</head>
<body>
 <div class="container">
     <div class="alert alert-primary">Update!</div>
     <div class="alert alert-success">Update 2</div>
     <div class="alert alert-danger">Update!</div>
 </div>
</body>
</html>