Need Some help with javascript

Dear All,
I have two preoccupations
- i need some help with the script on adode.
my problem is as follows.
several parts are delivered to different customers in different years and city.
I would like dropdown 4 to display only the serial numbers of the items delivered that year, depending on the year, customer and town selected.
-- some information is pre-recorded for example (as in the photo)
By default, only drop-down 1 is displayed.
when I select a year, drop-down 2 is displayed,
when I select a customer, drop-down 3 is displayed,
and when I choose city, I can't display the serial numbers.
- is it possible to create a table like the one below in abode, so that + allows me to add rows and - to reduce them?

thanks in advance
