Deny URL's in comments [HELP]

Good Afternoon,

I am having a problem with this (https://cutephp.com/forum/index.php?showtopic=23066&pid=141697&st=0&#entry93062) I did all of the steps, the problem is that you can't post URL's like http://google.com but when I try without the http:// like example google.com it goes through. Is there anyway to block all of the URl's without http://?

Thanks,
Matthew