Highcharts.getJSON('https://cdn.jsdelivr.net/gh/highcharts/highcharts@v7.0.0/samples/data/world-population-density.json', function (data) {

    // Initiate the chart
    var chart = Highcharts.mapChart('container', {

        title: {
            text: 'Set random data'
        },

        legend: {
            title: {
                text: 'Population density per km²'
            }
        },

        colorAxis: {
            min: 1,
            max: 1000,
            type: 'logarithmic'
        },
        series: [{
            data: data,
            mapData: Highcharts.maps['custom/world'],
            joinBy: ['iso-a2', 'code'],
            name: 'Population density',
            states: {
                hover: {
                    color: '#a4edba'
                }
            },
            tooltip: {
                valueSuffix: '/km²'
            }
        }]
    });

    // Activate the button
    document.getElementById('setdata').addEventListener('click', function () {
        data.forEach(function (p) {
            p.value = Math.round(Math.random() * 1000);
        });
        chart.series[0].setData(data);
    });
});
