anychart.onDocumentReady(function () {
var chart = anychart.area();
var series = chart.splineArea([
{x: 'January', value: 5},
{x: 'February', value: 6},
series.fill(function () {
return this.sourceColor + ' 0.4';
chart.title('Set fill parameter as a function');
chart.container('container');