Form Validator

I need a form validator to check fields have been entered properly for a mailing list. The fields are: -- Name -- Surname -- Gender -- Date of Birth (Pull-Down) -- Month of Birth (Pull-Down) -- Year of Birth (Pull-Down) -- Email Address -- Email Status (Pull-Down) -- Mailing Address -- Mailing Suburb/City/Town -- Mailing Postcode -- Mailing State -- Mailing Country -- Mailing Status (Pull-Down) -- Mobile/SMS number -- SMS Status -- Comments I have the form already to go.