Parsing domain from a URL

Question

I need to build a function which parses the domain from a URL.

So, with

http://google.com/dhasjkdas/sadsdds/sdda/sdads.html

or

Answer 1

function get_domain($url = SITE_URL)
{
    preg_match("/[a-z0-9\-]{1,63}\.[a-z\.]{2,6}$/", parse_url($url, PHP_URL_HOST), $_domain_tld);
    return $_domain_tld[0];
}

get_domain('http://www.cdl.gr'); //cdl.gr
get_domain('http://cdl.gr'); //cdl.gr
get_domain('http://www2.cdl.gr'); //cdl.gr