I created a little javascript which only allows numbers and letters in the username field. If they type in something else, or even a space, a popup comes up and tells them they need to redo it and it wipes out the text they put in the field.
I'm no pro. I did an "onkeyup" to trigger the javascript so I had to disable username checking which also works on key up.
I also put maxlength="16" in there to restrict the username to 16 characters.
Attached is a .zip file of my cb.core.php file which has everything working. (components/com_comprofiler/plugin/user/plug_cbcore/cb.core.php)
You can see it in action on the registration page of
www.thegolfspace.com
or
www.themacspace.com
This is a hack for cb 1.1 and NOT any earlier version. When a new version comes out, this would be wiped out by the upgrade so you'd have to put the code in again...
I make no guarantees but it works on my sites.
Attachment cb-7d9ce577111522b3ed578044c73ea6f8.zip not found