I have two elements. The first one contains countries (e.g. USA, Canada, England, Russia, Poland...) and the second one is hidden, containing cit
Listen to the change event for the select list. In the change event, if the selected value is "USA" or "Canada" then show the other select list, otherwise hide it.
See an example.
Assuming the select structure looks like this:
Listen to the change event on the countries array.
$("#countries").change(function() {
// find the selected country
var selectedCountry = $(this).val();
// if US or Canada
if(selectedCountry == "USA" || selectedCountry == "Canada") {
// show the cities list
$("#cities").show();
}
// otherwise hide it
else {
$("#cities").hide();
}
});