Form Fields Dependency

[eluser]Unknown[/eluser]
Hello.

I'm a newbie in PHP and CI.
Does anyone know if CI has a library that can handle Form fields dependency?
What I meant here is that the options in one field is dependent on the selected
option in another field. I understand this can be done in JavaScript or AJAX,
I was just just wondering if there's another option(CI Library...i.e. Validation).

Thanks.
CI_Believer