anychart.onDocumentReady(function () {
var data1 = [166, 43, -79, -46, 84, NaN];
var data2 = [50, -25, 30, 28, 83, NaN];
var chart = anychart.waterfall();
chart.addSeries(data1, data2);
var series = chart.getSeries(0);
var index = series.getIndex();
chart.title('Index of the first series is ' + index);
chart.container('container');