ColdFusion/Oracle system needs field validation

I have a ColdFusion/Oracle application undergoing gradual review. An area that I have inconsistent results in is field/data validation. For a small number of fields - less than 10 -? I need the following validation: * That mandatory fields have an entry * That field entries are of the right type (eg numeric) * That text fields don't exceed a certain length I'm happy to take advice, but would initiatlly expect this to be client side validation, with appropriate error messages/user guidance.