JSONP in PHP

jsonp.php

function sendJsonResponse($map) {
  $json = json_encode($map);
  // JSON
  if(!isset($_GET['callback'])){
    header("Content-type: application/json");
    echo $json;
    return;
  }

  // JSONP
  header("Content-type: application/javascript");
  $callback=$_GET['callback'];
  print <<<END
$callback($json);
END;
}