Function to verify URL?

[eluser]the jan[/eluser]
Hi!

I've been looking through the docs for an easy way to verify if a URL entered into a form is valid but I can't find a function. I know about the Verification Class and it contains a way to validate email adresses:

Code:

$rules['email'] = "required|valid_email";

Is there such an easy way for URLs? Or do I have to write my own regex?

Thanks,
Jan