Adding logic to form

I've got a form here to which I'd like some logic added. Some logic is to help this form be submitted more easily. Some just because I'm curious as to how to do it. As such, I'd like all amendments commented so I can apply similar logic to other forms I create in future. - Next to both the "First name" and last "Name fields" are sentences which I'd like to appear in a display box only on focus. - Under the email address field is a question mark icon, next to which is the sentence "Please provide us with your primary email address." I'd only like this sentence to appear when the question mark icon is clicked. - Next to the password and confirm password fields are ticks and crosses. I'd like them invisible to start with. I'd like a min of 4 characters set to these fields as well as a max of 10 (max already done). When a user types 4 characters in the password field, I'd like the tick to become visible next to it. When they start typing in the confirm_password field, I'd like the tick to become visible if and when the two fields match. If the password and confirm password fields don't match, I'd like the cross next to the confirm_password field to become visible. - I'd like a date picker widget to be used with the date of birth (dob) field. Preferably one with either a dropdown menu for year, or one where year can be typed in, so the user doesn't have to hit the back button many times to get to their year of birth. - After the racehistory field, I'd like the next few fields (recent_finish, prev_fin_count, result1 through to result5 and hat_size) initially invisible. - If "Previous finisher" is selected for race history, I'd like recent_finish and prev_fin_count to become visible and mandatory. - If "Previous finisher" is not selected for race history, I'd like result1 through to result5 and hat size to become visible, with result1 and hat_size being mandatory. That's about it. Look forward to hearing from you, Dave ## Deliverables 1) All deliverables will be considered "work made for hire" under U.S. Copyright law. Employer will receive exclusive and complete copyrights to all work purchased. (No 3rd party components unless all copyright ramifications are explained AND AGREED TO by the employer on the site per the worker's Worker Legal Agreement). ## Platform php, mysql and javascript may be used for this form.