Using "labelFunction" to work around very small numbers getting reformatted to scientific notation

HTML

<script type="text/javascript" src="http://www.amcharts.com/lib/3/amcharts.js"></script>
<script type="text/javascript" src="http://www.amcharts.com/lib/3/serial.js"></script>
<script type="text/javascript" src="http://www.amcharts.com/lib/3/themes/none.js"></script>
<script type="text/javascript" src="http://www.amcharts.com/lib/3/amstock.js"></script>
<div id="chartdiv"></div>

CSS

body {
    font-family: Verdana;
    font-size: 12px;
    padding: 10px;
}
#chartdiv {
	width	: 100%;
	height	: 500px;
}

JavaScript

// let's add a "noExponents" method to Number
// courtesy: http://stackoverflow.com/a/16139848/634045
Number.prototype.noExponents = function () {
    var data = String(this).split(/[eE]/);
    if (data.length == 1) return data[0];

    var z = '',
        sign = this < 0 ? '-' : '',
        str = data[0].replace('.', ''),
        mag = Number(data[1]) + 1;

    if (mag < 0) {
        z = sign + '0.';
        while (mag++) z += '0';
        return z + str.replace(/^\-/, '');
    }
    mag -= str.length;
    while (mag--) z += '0';
    return str + z;
}


var chartData = generateChartData();

function generateChartData() {
    var chartData = [];
    var firstDate = new Date(2012, 0, 1);
    firstDate.setDate(firstDate.getDate() - 1000);
    firstDate.setHours(0, 0, 0, 0);

    for (var i = 0; i < 1000; i++) {
        var newDate = new Date(firstDate);
        newDate.setHours(0, i, 0, 0);

        var a = (Math.round(Math.random() * (40 + i)) + 100 + i) / 100000000000;
        var b = Math.round(Math.random() * 100000000);

        chartData.push({
            date: newDate,
            value: a,
            volume: b
        });
    }
    return chartData;
}

var chart = AmCharts.makeChart("chartdiv", {

    type: "stock",
    "theme": "none",
    pathToImages: "http://www.amcharts.com/lib/3/images/",

    categoryAxesSettings: {
        minPeriod: "mm"
    },

    valueAxesSettings: {
        usePrefixes: false
    },

    dataSets: [{
        color: "#b0de09",
        fieldMappings: [{
            fromField: "value",
            toField: "value"
        }, {
            fromField: "volume",
            toField: "volume"
        }],

        dataProvider: chartData,
        categoryField: "date"
    }],


    panels: [{
            showCategoryAxis: false,
            title: "Value",
            percentHeight: 70,

            valueAxes: [{
                // we'll use labelFunction to custom-format the labels using the new method
                // we created...