Change the Value of Parent Dropdown using Jquery and the child will show the data

This is what I want to do, when I click Edit Button it will get the data in table then it will send it to dropdowns.

$("[id*=lnkEdit]").click(function() {
	var row = $(this).closest("tr");
	var country = row.find("[id*lblCountryID]").eq(1).html();
	var state = row.find("[id*lblStateID]").eq(2).html();
	var city = row.find("[id*lblCityID]").eq(3).html();
	
	$("#ctl00_contentplaceholder1_ddlCountries").val(country);
	$("#ctl00_contentplaceholder1_ddlStates").val(state);
	$("#ctl00_contentplaceholder1_ddlCities").val(city);
	return false;
});

That's the reason why I am asking how to get the child dropdown data when the parent dropdown was changed using jquery