I want to use a "Match Regular Expression" in my user registration options to only allow a-z, A-Z and 0-9 usernames (no spaces, dots or any of that stuff). I did a bit of research and I think I've got the answer, but I am seeking verification as I don't know what I'm doing.
Is this what I would need?: ^[A-Za-z0-9]
Any help would be appreciated. Thanks!