What PHP function can be used to highlight and display the source code of a webpage on another webpage?

To highlight and display the source code of a webpage on another webpage, you can use the `highlight_string()` function in PHP. This function takes a string of PHP code as input and outputs it with syntax highlighting.

<?php
$url = 'http://example.com'; // URL of the webpage whose source code you want to display
$html = file_get_contents($url); // Get the HTML source code of the webpage
highlight_string($html); // Display the highlighted source code on the webpage
?>