I couldn't find a github repo for the online version to add an issue, so I will just report it here.
The Online version seem to have this same bug as the android version: https://github.com/tasermonkey/android-passwordmaker/issues/10
Basically the bug is, for domains like "www.google.co.uk
" when you have the "domain" option checked, its hashing just "co.uk" instead of "google.co.uk". See the github issue for more information.
Which is sort of expected, as I based my version off of the online version when I was testing.
But I think its a legit bug.