Are there any client-side validation gems similar to client_side_validations (https://github.com/bcardarella/client_side_validations) for Rails 2.x?
I am actually in the process of backporting the current ClientSideValidations gem to Rails 2.x
https://github.com/bcardarella/client_side_validations-rails_2
It's not ready for public consumption yet, but you might want to keep an eye on it. It will inherit from the current gem and add the necessary functionality to Rails 2.x.