Dropdown menu background color change

Hello,

I'm a total rookie with Adobe Pro and I'm trying to figure out how to add javascript to my fillable pdf form.  More specifically, I have about 100 dropdown menus each with the same items to select: "1", "2", "3" and "4".  

I hoping there's a way to incorporate javascript to  each dropdown menu that would change the background color depending on which item is selected.  i.e

If "1" then background to red

If "2" then background to yellow

If "3" then background unchanged or white

If "4" then background to green

Is there an easy way to do this?

Thank you!