I have such a problem, I need to do so when I changed in multipe select selected value in changed map?

Question

JavaScript

<select id = "countries" multiple = "multiple>
    <option value = "1"> Russia</option>
    <option value = "2" selected> Russia</option>
    <option value = "3"> Russia</option>
    <option value = "4"> Russia</option>
</select>

<script>
    $(function() {
        google.charts.load('current', {
            'packages':['geochart'],
            // Note: you will need to get a mapsApiKey for your project.
            // See: https://developers.google.com/chart/interactive/docs/basic_load_libs#load-settings
            'mapsApiKey': 'AIzaSyD-9tSrke72PouQMnMX-a7eZSW0jkFMBWY'
        });
        google.charts.setOnLoadCallback(drawRegionsMap);
        function drawRegionsMap() {
            var data = google.visualization.arrayToDataTable([
                ['Country'],
                ['RUSSIA']
            ]);

            var options = {};

            var chart = new google.visualization.GeoChart(document.getElementById('regions_div'));

            chart.draw(data, options);
        }
        $('#countries').selectize({
            "maxItems" : 300,
            onChange:function(value){

            }
        });
    });
</script>