firstTextbox will accept input from the user , force the input to reflect on the calendar e.g, If a user type 09/04/2012 , this same date will show up from the calendar. Nevertheless, user can choose to type in input or select directly from the Calender.
secondTextbox will also accept user's input and force the input to reflect on the calendar, e.g if user type 07/22/2017, this same date will show up from the calendar. Nevertheless, user could either choose to type in the date or select from the calendar.
Here is where I have all the code that makes this application work.
Tip: Have you ever thought of getting the date you left your secondary school when you are 80 years old already? This application makes things of such easy.
Hope this helps you, comment by sharing your ideas to help others.