[cflsystems]

The use of js should be avoided whenever possible. XC has way too much of it as it is already.

Find the class responsible for displaying the address form. This will tell you which template(s) is used to display the different fields. You will need to modify the one showing the city field and eventually make it call another form field class to draw a dropdown. Within that same class you can hardcode the cities as default options array to be shown in the dropdown. If you want to make it more complicated and use the database you will have to create few more classes to be able to add cities from admin and relate them to the country in question.