Input Validation for text and/or numbers

Hi,
I´m using the extension InputValidation for setting username.

Checking the input field for free user names while the user is typing works fine.
How to allow user to use only characters and/or numbers like ‘mike123’ ?

The extension allows only latin alphabet letters like ‘mike’ or check a string if represents a number like ‘123’, but not a combination.

Any idea? Thank you.