test_preg_match

<?php

//从URL中获取主机名称
preg_match('@^(?:http://)?([^/]+)@i',
    "http://www.php.net/index.html", $matches);

$host = $matches[1];

//获取主机名称的后面两部分
preg_match('/[^.]+\.[^.]+$/', $host, $matches);

echo "domain name is: {$matches[0]}\n";

?>