How can i add title for c3.js chart

Question

trying to add title for c3 chart like this way.but it is not working . i want change the title in load time . now it is showing the title which i added in generate chart. how can i change the title on load time?

setTimeout(function () {
        _chartdata.load({
            columns: [
                [_footerheading, 5],
                ["others", 5]
            ],
            donut: {
                title: {
                    text: x+"%"
                  },
            }
        });
    }, 50);