I'm sorry to ask a question but I am useless when it comes to understanding regex code.

In a php module that I didn't write is the following function

```
function isURL($url = NULL) {
    if($url==NULL) return false;

    $protocol = '(http://|https://)';
    $allowed = '([a-z0-9]([-a-z0-9]*[a-z0-9]+)?)';

    $regex = "^". $protocol . // must include the protocol
                     '(' . $allowed . '{1,63}\.)+'. // 1 or several sub domains with a max of 63 chars
                     '[a-z]' . '{2,6}'; // followed by a TLD
    if(eregi($regex, $url)==true) return true;
    else return false;
}

```

Can some kind soul give me the replacement code for that with whatever is required to replace the eregi