PHP CORS Access Control Cross-Origin Header

php_cors_header_examples.php

<?php

// if you want pass all
header('Access-Control-Allow-Origin: *');

// if you want limit by domain
header('Access-Control-Allow-Origin: https://domain.com');

// if you want limit by multiple domains
// list of allowed domains
$allowed_domains = array(
  'domain.com',
  'domain2.com'
);
// find out current incoming client
if (array_key_exists('HTTP_ORIGIN', $_SERVER)) {     
  $origin = $_SERVER['HTTP_ORIGIN']; 
} else if (array_key_exists('HTTP_REFERER', $_SERVER)) {     
  $origin = $_SERVER['HTTP_REFERER']; 
} else {     
  $origin = $_SERVER['REMOTE_ADDR']; 
}
// check if it matches
if (in_array($allowed_domains, $origin)) {
  header('Access-Control-Allow-Origin: ' . $origin);
}

?>