amcharts Area with time based data

HTML

<script src="http://www.amcharts.com/lib/amcharts.js" type="text/javascript"></script>
<div id="chartdiv" style="width: 100%; height: 362px;"></div>

JavaScript

var chart;
var chartData = [];

// generate some random data, quite different range
function generateChartData() {
    // current date
    var date = new Date();
    // now set 1000 minutes back                 
    date.setMinutes(date.getDate() - 1000);

    // and generate 1000 data items
    for (var i = 0; i < 90000; i++) {
        var newDate = new Date(date);
        // each time we add one minute
        newDate.setMinutes(newDate.getMinutes() + i);
        // some random number      
        var visits = Math.round(Math.random() * 40) + 10;
        // add data item to the array                          
        chartData.push({
            date: newDate,
            visits: visits
        });
    }
}

AmCharts.ready(function() {
    // generate some random data
    generateChartData();

    // SERIAL CHART
    chart = new AmCharts.AmSerialChart();
    chart.pathToImages = "http://www.amcharts.com/lib/images/";
    chart.autoMarginOffset = 3;
    chart.marginRight = 15;
    chart.zoomOutButton = {
        backgroundColor: '#000000',
        backgroundAlpha: 0.15
    };
    chart.dataProvider = chartData;
    chart.categoryField = "date";

    // data updated event will be fired when chart is displayed,
    // also when data will be updated. We'll use it to set some
    // initial zoom
    chart.addListener("dataUpdated", zoomChart);

    // AXES
    // Category
    var categoryAxis = chart.categoryAxis;
    categoryAxis.parseDates = true; // in order char to understand dates, we should set parseDates to true
    categoryAxis.minPeriod = "mm"; // as we have data with minute interval, we have to set "mm" here.             
    categoryAxis.gridAlpha = 0.07;
    categoryAxis.showLastLabel = false;
    categoryAxis.axisColor = "#DADADA";

    // Value
    var valueAxis = new AmCharts.ValueAxis();
    valueAxis.gridAlpha = 0.07;
    valueAxis.title = "Unique visitors";
    chart.addValueAxis(valueAxis);

    // GRAPH
    var graph = new AmCharts.AmGraph();
   ...