Highcharts.ganttChart('container', {

    title: {
        text: 'Highcharts Gantt Chart'
    },

    yAxis: {
        uniqueNames: true
    },

    accessibility: {
        point: {
            descriptionFormatter: function (point) {
                var completedValue = point.completed ?
                        point.completed.amount || point.completed : null,
                    completed = completedValue ?
                        ' Task ' + Math.round(completedValue * 1000) / 10 + '% completed.' :
                        '';
                return Highcharts.format(
                    '{point.yCategory}.{completed} Start {point.x:%Y-%m-%d}, end {point.x2:%Y-%m-%d}.',
                    { point, completed }
                );
            }
        }
    },

    lang: {
        accessibility: {
            axis: {
                xAxisDescriptionPlural: 'The chart has a two-part X axis showing time in both week numbers and days.'
            }
        }
    },

    series: [{
        name: 'Project 1',
        data: [{
            start: Date.UTC(2018, 11, 1),
            end: Date.UTC(2018, 11, 2),
            completed: 0.95,
            name: 'Prototyping'
        }, {
            start: Date.UTC(2018, 11, 2),
            end: Date.UTC(2018, 11, 5),
            completed: 0.444,
            name: 'Development'
        }, {
            start: Date.UTC(2018, 11, 8),
            end: Date.UTC(2018, 11, 9),
            completed: 0.141,
            name: 'Testing'
        }, {
            start: Date.UTC(2018, 11, 9),
            end: Date.UTC(2018, 11, 19),
            completed: {
                amount: 0.3,
                fill: '#fa0'
            },
            name: 'Development'
        }, {
            start: Date.UTC(2018, 11, 10),
            end: Date.UTC(2018, 11, 23),
            name: 'Testing'
        }]
    }]
});

// Activate the custom button
document.getElementById('pdf').addEventListener('click', function () {
    Highcharts.charts[0].exportChart({
        type: 'application/pdf'
    });
});