$(document).ready(function(){
        $('#country').change(function(){
            var id_country = $(this).val();
            $.ajax({
                    type: "POST",
                    url: "ajax_base.php",
                    data: "action=showRegionForInsert&id_country="+id_country,
                    cache: false,
                    success: function(responce){
                        $('#selectDataRegion').html(responce);
                    }
                });
        });
        $('#selectDataRegion').on('change','select',function(){
            var id_region = $(this).val();
            $.ajax({
                    type: "POST",
                    url: "ajax_base.php",
                    data: "action=showCityForInsert&id_region="+id_region,
                    cache: false,
                    success: function(responce){ $('#selectDataCity').html(responce); }
            });
        })
    })