What are the potential issues with including a complete HTML document within a div using PHP?

Including a complete HTML document within a div using PHP can lead to invalid HTML structure and potential conflicts with existing CSS styles. To solve this issue, you can use PHP's output buffering functions to capture the HTML content and then insert it into the div element.

<?php
ob_start();
?>
<!DOCTYPE html>
<html>
<head>
    <title>My Page</title>
</head>
<body>
    <div>
        <?php echo "Content goes here"; ?>
    </div>
</body>
</html>
<?php
$html = ob_get_clean();
?>

<div>
    <?php echo $html; ?>
</div>