ccess-Control-Allow-Origin' header code example

Example 1: access-control-allow-origin

Access-Control-Allow-Origin: *

Example 2: allow cross origin

Access-Control-Allow-Origin: *
Access-Control-Allow-Origin: <origin>
Access-Control-Allow-Origin: null

Example 3: cross origin even with allow header

header('Access-Control-Allow-Origin: http://localhost:8100');
header ("Access-Control-Expose-Headers: Content-Length, X-JSON");
header ("Access-Control-Allow-Methods: GET, POST, PATCH, PUT, DELETE, OPTIONS");
header ("Access-Control-Allow-Headers: Content-Type, Authorization, Accept, Accept-Language, X-Authorization");
header('Access-Control-Max-Age: 86400');

if ($_SERVER['REQUEST_METHOD'] === 'OPTIONS') {
    // The request is using the POST method
    header("HTTP/1.1 200 OK");
    return;

}