Adding form validation and extra field

I have a PHP form designed, however, the validation is not working. Need a few of these added. See details. ## Deliverables The form is a Contact Us form. I need the form made in two ways, just in case I want to use a different version. Version 1: We have a field that is "What is your email address"? I need a new field added "Please re-enter your email address". When customer clicks on "Submit", system should validate that both email addresses match. If email addresses do not match, a popup will say, "Email address fields do not match." If there is a match, system will send contact form. Version 2: For field, "What is your email address", please validate that an "@" symbol and at least one "." has been put in that field. If there is no "@" symbol or ".", please popup an error that says, "Please enter a correct email address". Do NOT add another field. I will email you the Contact Us files and the Thank you page of the form. I will need work done for both versions and then sent back to me. We will also need to make sure that emails are still sent and everything works as before, including the new features. Both versions should be sent in separate zip files.