PHP Headers allow CORS

PHP Headers allow CORS.php

<?php
 
    /* set the HTTP_ORIGIN to the requester origin if empty */
    if( isset( $_SERVER['HTTP_ORIGIN'] ) && $_SERVER['HTTP_ORIGIN'] != '' )
    {

        header("Access-Control-Allow-Origin: {$_SERVER['HTTP_ORIGIN']}");
        header('Access-Control-Allow-Credentials: true');
        header('Access-Control-Max-Age: 0');    // cache for 0 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, PUT, POST, DELETE, OPTIONS");
        if( isset($_SERVER['HTTP_ACCESS_CONTROL_REQUEST_HEADERS']))
            header("Access-Control-Allow-Headers: {$_SERVER['HTTP_ACCESS_CONTROL_REQUEST_HEADERS']}");
        exit;
    }