//Include latest jQuery library (current version 3.6.0)
jQuery(function($) {
    var locations = {
        'Germany': ['Berlin','Bonn','Duesseldorf','Eschborn'],
        'India': ['Bengaluru','Chennai','Kolkata','Mumbai','New Delhi'],
        'Spain': ['Barcelona','Madrid','Toledo'],
        'USA': ['Boston','Chicago','Los Angeles','New York'],
        'Mexico': ['Puebla','Cancun','Mexico City'],
        'Russia': ['Irkutsk','Kursk','Moscow','St. Petersburg'],
    }
    
    var $locations = $('#location');

    $('#country').change(function () {
        var country = $(this).val(), cityidx = locations[country] || [];
        
        var html = $.map(cityidx, function(cityidx){
            return '' + cityidx + ''
        }).join('');
        $locations.html(html)
    });
});