html, body, #container {

    width: 100%;

    height: 100%;

    margin: 0;

    padding: 0;

}

anychart.onDocumentReady(function () {

    var chart = anychart.area();

​

    var series = chart.stepArea([

        {x: "January", value: 125},

        {x: "February", value: 132},

        {x: "March", value: 141},

        {x: "April", value: 158},

        {x: "May", value: 133},

        {x: "June", value: 143}

    ]);

​

    // Set fill.

    series.fill(function () {

        return this.sourceColor + " 0.4";

    });

​

    chart.title("Set fill parameter as a function");

    chart.container("container");

    chart.draw();

});