Have a form with 2 text fields, txt1 and txt2. The user has to enter a code between 01 and 99 into txt1. If the entered code in txt1 is between 71 and 84, txt2 must be completed by entering a code between 01 and 73 or 85 to 99.Wanted, that when the code was entered into txt1, if it was 71 to 84 that...