Retrieve the variable php

How do I do to get the variable test?

<?php

$test = 1;

if ($_GET['mode']=="save") {

$score = $_GET['score'];

}

?>

I'm not getting the Ajax.LastData

Actually I want to send a variable to the php and see if it is equal to the variable test. If yes it is, if not he sends to construct a message. How can I do this?

Are you making a cross-domain request? If so have you checked the manual section on it?