The CountryRegionCityJax firstly populates a dropdown box with a list of countries. When a country is selected, the next dropdown box is populated with a list of regions from that country. When a region is selected, a list of cities in that region populates a third dropdown.
All three elements are talkers, because data gets loaded into them. Country and region are listeners, because events that take place on them result in a subsequent action (country populates region, region populates city). City is not a listener, because changing the city doesn't have any effect.
Note: there is an intentional delay on loading of data to demonstrate how the controls behave while data is being downloaded