Exercise 5 Create a function that will be called on click of a button. The surface area of a rectangle will be supplied after user will have specified the width and the height of a rectangle. Here's the formula to calculate the surface area of a square/rectangle: width x lenght = surface area Exercise 5 Create a function that will be called on click of a button. The surface area of a rectangle will be supplied after user will have specified the width and the height of a rectangle. Here's the formula to calculate the surface area of a square/rectangle: width x lenght = surface area