PHP: get subdomain from host

<?php $subdomain = substr_count($_SERVER['HTTP_HOST'], '.') > 1 ? substr($_SERVER['HTTP_HOST'], 0, strpos($_SERVER['HTTP_HOST'], '.')) : ''; // Where host is 'www.example.com' $subdomain will be 'www' // Where host is 'example.com' $subdomain will be '' // Where host is 'sub2.sub1.example.com' $subdomain will be 'sub2' // Where host is 'localhost' $subdomain will be ''