How can PHP access the $_GET data passed through the URL of a page when using jQuery AJAX?

When using jQuery AJAX to send data to a PHP script, the $_GET data passed through the URL may not be directly accessible in the PHP script. To access this data, you can use the $_REQUEST superglobal which combines data from $_GET, $_POST, and $_COOKIE. This allows you to retrieve the data sent through the URL in the PHP script.

$data_from_url = $_REQUEST['data']; // Access the data passed through the URL
echo $data_from_url; // Output the data for testing purposes