headers.php

<?php
  header("Access-Control-Allow-Origin: *");
  header("Access-Control-Allow-Credentials: true");
  header("Access-Control-Allow-Methods: GET,HEAD,OPTIONS,POST,PUT");
  header("Access-Control-Allow-Headers: Access-Control-Allow-Headers, Origin,Accept, X-Requested-With, Content-Type, Access-Control-Request-Method, Access-Control-Request-Headers");

  // ou
  header("Access-Control-Allow-Origin: * ");
  header("Content-Type: application/json; charset=UTF-8");
  header("Access-Control-Allow-Methods: POST");
  header("Access-Control-Max-Age: 3600");
  header("Access-Control-Allow-Headers: Content-Type, Access-Control-Allow-Headers, Authorization, X-Requested-With");