Javascript - jQuery JSONP

1. Url:

http://service.example.com/word/list.php?callback=?

2. Call(Javascript):

$.getJSON(url, data, function(response){});

3. Server side(PHP):

$response = json_encode(array("data"=> $words));
if(array_key_exists('callback', $_REQUEST))
{
    $callback = $_REQUEST['callback'];
    $response = $callback . "(" . $response . ");";
}