javascript - Regular Expression: Allow letters, numbers, and spaces (with at least one letter or number)

Question

I'm currently using this regex ^[A-Z0-9 _]*$ to accept letters, numbers, spaces and underscores. I need to modify it to require at least one number or letter somewhere in the string. Any help would be appreciated!

This would be for validating usernames for my website. I'd actually like to support as many characters as I can, but just want to ensure that I prevent code injection and that characters will display fine for all users. So I'm definately open to regex validation suggestions that would support a wider set of characters.

Answer 1

You simply need to specify your current RE, followed by a letter/number followed by your current RE again:

^[A-Z0-9 _]*[A-Z0-9][A-Z0-9 _]*$

Since you've now stated they're Javascript REs, there's a useful site here where you can test the RE against input data.

If you want lowercase letters as well:

^[A-Za-z0-9 _]*[A-Za-z0-9][A-Za-z0-9 _]*$