On your index
<?php include 'main-minify.php';?>
<!DOCTYPE html>
<html>
<head>
<title>Demo for minifier</title>
</head>
<body>
<h1>Hello World</h1>
</body>
</html>
<?php include 'end-minify.php';?>Example :
<?php
// Import the HTMLMinifier
require_once 'minify/index.php';
// HTML source to be minified
$htmlpage = file_get_contents('index.html');
// Minified version of the page
echo HTMLMinifier::process($htmlpage);
?>