I created a booking system, however for the passport expiry
input field, i need to put the validation of 6 months. It means the
users cannot submit the page if his passport expiry is less than 6
months comparing to the tour start date. Also, the system should be
able to prompt an error message if submission is unsucessful.
How am I going to put this function into the Submit button?
P.S. I am using Expression Web to do the website and Javascript
or PHP would do.