Below there is a membership calculator form. It has 3 fields: Membership Type (pulldown), Years (input) and Costs (input). User can use the pulldown to select which plan user wants to choose (Basic = 10€, Premium=15€, Gold=20€) and then enter the number of years he wants to pay for.
Update the code of the form so that:
a) the Costs-field should display the total costs of the subscription
b) If the user chooses to pay for more than 2 years, he will get a 20% discount. Notify the user when he is eligible to get the discount, by showing a text next to form.
c) Should he pay for 5 years or more, he will get the normal 20% discount, but will also be given an extra 5€ discount with a special greetings text on screen.