PHP is a server-side programming language which can generate HTML to send. Unlike JavaScript, PHP is run on the web server.
<html>
<head>
<title>This is the site's title page.</title>
</head>
<body>
<h1>This is a heading</h1>
<p>This is a paragraph of text...</p>
<p>The second paragraph goes here.</p>
<p>The result of 2 + 2 is <?php echo(2 + 2); ?></p>
</body>
</html>