function updateChart(chartDivId, data, chartColors) {
    var chart = findChart(chartDivId);
    chart.dataProvider = data;
    if (chartColors) {
        chart.colors = chartColors;
    }
    chart.validateData();
    checkEmptyData(chart);
};
function findChart(id) {
    var matchedCharts = AmCharts.charts.filter(function (chart, index) {
        return chart.div && chart.div.id === id;
    })
    if (matchedCharts.length) {
        return matchedCharts[0];
    }
};
function invalidateChartSize(chartId) {
    var chart = findChart(chartId);
    chart.invalidateSize();
};
function checkEmptyData(chart) {
    chart.clearLabels();

    if (chart.dataProvider === undefined || 0 == chart.dataProvider.length) {
        if (chart.type != "pie") {
            // set min/max on the value axis
            //chart.valueAxes[0].minimum = 0;
            //chart.valueAxes[0].maximum = 100;

            // add dummy data point
            var dataPoint = {
                dummyValue: 0
            };
            dataPoint[chart.categoryField] = '';
            chart.dataProvider = [dataPoint];

            // add label
            chart.addLabel("50%", '50%', 'The chart contains no data', 'center', 12, 0, 0.5);

            // set opacity of the chart div
            //chart.chartDiv.style.opacity = 0.5;

            // redraw it
            //chart.validateNow();
        } else {
            var dp = {};
            dp[chart.titleField] = "";
            dp[chart.valueField] = 1;
            chart.dataProvider.push(dp)

            var dp = {};
            dp[chart.titleField] = "";
            dp[chart.valueField] = 1;
            chart.dataProvider.push(dp)

            var dp = {};
            dp[chart.titleField] = "";
            dp[chart.valueField] = 1;
            chart.dataProvider.push(dp)

            // disable slice labels
            //chart.labelsEnabled = false;

            // add label to let users know the chart is empty
            chart.addLabel("50%", "60%", "The chart contains no data", "center", 12, 0, 0.1);

            // dim the whole chart
            //chart.alpha = 0.3;

            chart.validateNow();
        }
    }
};