JSFiddle - React, Tailwind, and code Playground

HTML

Countries <div id='divTravelToCountryId'></div>
<br/>
Cities <select id='TravelToCityId'></select>

JavaScript

$(function() { 
    
    // Models
    
    var countries = 
    [
        { 
            CountryId: 1, CountryName: 'Philippines',
            Cities :
            [
                { CityId: 1, CityName: 'Manila' },
                { CityId: 2, CityName: 'Makati' },
                { CityId: 3, CityName: 'Quezon' },            
            ]            
        },
        { 
            CountryId: 2, CountryName: 'Canada',
            Cities:
            [
                { CityId: 4, CityName: 'Toronto' },
                { CityId: 5, CityName: 'Alberta' },
                { CityId: 6, CityName: 'Winnipeg' },
            ]           
            
        },
        { 
            CountryId: 3, CountryName: 'China',
            Cities:
            [
                { CityId: 7, CityName: 'Beijing' },
                { CityId: 8, CityName: 'Shanghai' }
            ]           
        },    
    ];    
           
    
    
    // Controller that live two lives,
    // can't focus well on model :-)
    
    // Populate then wire event...
    
    var divCountry = $('#divTravelToCountryId');
    
        
    $.each(countries, function() {
        
        var option = $(
            '<input type="radio" ' + 
            ' id="TravelToCountryId"' + 
            ' name="TravelToCountryId" />').val(this.CountryId);
        
        divCountry.append(option).append(' ' + this.CountryName).append('<br/>');
        
    });
    
    var country = $('input[name=TravelToCountryId]');
    var city = $('#TravelToCityId');
    
    
    $(country).change(function() {     
        filterCitiesByCountry();
    });
    
    // ...Populate then wire event
    
    
    // Init...
    var initialCountryId = countries[1].CountryId;     
    $(country).filter('[value="' + initialCountryId + '"]').prop('checked',true);        
    filterCitiesByCountry();
    // ...Init
    
        
    
    
    function filterCitiesByCountry() {
                
        var selectedCountryId =...