Headers to prevent CORS errors.

index.php

 // Allow from any origin
    if (isset($_SERVER['HTTP_ORIGIN'])) {
      header("Access-Control-Allow-Origin: *");
      // header('Access-Control-Allow-Credentials: true');
      // header('Access-Control-Max-Age: 86400');    // cache for 1 day

    }

  // Access-Control headers are received during OPTIONS requests
  if ($_SERVER['REQUEST_METHOD'] == 'OPTIONS') {

    if (isset($_SERVER['HTTP_ACCESS_CONTROL_REQUEST_METHOD']))
      header("Access-Control-Allow-Methods: GET, POST, OPTIONS, PUT, DELETE");

    if (isset($_SERVER['HTTP_ACCESS_CONTROL_REQUEST_HEADERS']))
      header("Access-Control-Allow-Headers: {$_SERVER['HTTP_ACCESS_CONTROL_REQUEST_HEADERS']}");

    exit(0);
  }