How to show price depending on two selected select?

Question

JavaScript

Good afternoon. Please tell me how to implement the following:
you need to show the price depending on the selected two selects ... let's say a person selects a city district in the first select, selects the distance in the second, and the price is displayed in the div. It would be very cool if the second select was inactive until the first one was selected.
It is desirable that all this be without Ajax, because. values ​​will be about 15 in total.

I found a basically similar script www.appelsiini.net/projects/chained , but I don't understand how to make the final amount.

Answer 1

So?