// Warning: This can be manipulated by hackers!
// If this is problematic, store the domain in a config file
$currentDomain = $_SERVER['SERVER_NAME'];
parse_url('http://www.website.com/hey.php', PHP_URL_HOST);
$url = 'http://google.com/dhasjkdas/sadsdds/sdda/sdads.html';
$parse = parse_url($url);
echo $parse['host']; // prints 'google.com'
echo $_SERVER['SERVER_NAME']; //Outputs www.example.com