How to bind the choice of city to the selected country?

Question

MySQL

Greetings!
There is a delivery form, it has two fields: Country and City .
The mysql database has a list of cities that are offered for selection when entering letters in the City field .
How to make it so that only those cities that correspond to the selected country are offered?
Now, no matter which country I choose, all cities are offered, although there is a link to the country id in the mysql database.

Answer 1

мне в голову только react.js пришёл
но это без mysql

Answer 2

Как делается выборка? Или "я его поставил и запустил, оно не работает"?