On Tue, Jan 07, 2014 at 03:30:25PM -0800, Jared Zimmerman wrote:
I think their might be some misunderstanding as to what I'm proposing, my suggestion is that is is literally impossible to type a user name that is incompatible with our system, there would be no before and after, there would be no submit and then show a different user name, as the user types in the input field only acceptable characters and formats are accepted, characters that aren't allowed either don't show up and all or are automatically replaced as the user types, if they type i as the first character I is shown instead. there is not "error" step in the process.
This is a super painful usability issue - if someone types in characters, they expect those characters to show up in the input box. You can give them feedback about it, but simply *ignoring* the typing is not the way to do this.
See also: Password input boxes that silently ignore characters past 20 or 15 or whatever. It makes it impossible to use the site. This is less bad, but still not great.