<!DOCTYPE html>
<title>My Example</title>
<style>
.box {
background: orange;
color: white;
width: 150px;
padding: 20px;
margin: 10px;
}
</style>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>
<script>
$( function() {
$( "button" ).click( function() {
$( ".box" ).append( "<p>Surprise!</p>" );
});
</script>
<button>Add Content</button>
<div class="box">
<p>Main content.</p>
</div>
