How can absolute paths be used in PHP includes to ensure consistency across different servers?

When including files in PHP, using absolute paths instead of relative paths ensures consistency across different servers. This is because absolute paths specify the exact location of the file regardless of the server's file structure. To use absolute paths, you can use the $_SERVER['DOCUMENT_ROOT'] variable to get the root directory of the server and concatenate it with the file path.

<?php
include $_SERVER['DOCUMENT_ROOT'] . '/path/to/include/file.php';
?>