jqxChart date problem

by kaeldric

HTML

<script src="http://jqwidgets.com/public/jqwidgets/jqx-all.js"></script>
<link rel="stylesheet" href="http://jqwidgets.com/public/jqwidgets/styles/jqx.base.css">
<div id='chartContainer' style="width:850px; height:500px"></div>

JavaScript

$(document).ready(function () {
    // prepare the data
    var data = [{
        Person: "Planning",
        M1_From: new Date(2014, 0, 1),
        M1_To: new Date(2014, 0, 5),
        M2_From: new Date(2014, 0, 5),
        M2_To: new Date(2014, 0, 10)
    }, {
        Person: "Dev 1",
        M1_From: new Date(2014, 0, 5),
        M1_To: new Date(2014, 0, 7),
        M2_From: new Date(2014, 0, 9),
        M2_To: new Date(2014, 0, 17)
    }, {
        Person: "Dev 2",
        M1_From: new Date(2014, 0, 5),
        M1_To: new Date(2014, 0, 12),
        M2_From: new Date(2014, 0, 14),
        M2_To: new Date(2014, 0, 22)
    }, {
        Person: "QA 1",
        M1_From: new Date(2014, 0, 7),
        M1_To: new Date(2014, 0, 14),
        M2_From: new Date(2014, 0, 14),
        M2_To: new Date(2014, 0, 25)
    }];
    var toolTipCustomFormatFn = function (value, itemIndex, serie, group, categoryValue, categoryAxis) {
        var dataItem = data[itemIndex];
        return '<DIV style="text-align:left"><b>Team: ' + categoryValue +
            '</b><br />Start day: ' + value.from +
            '<br />End day: ' + value.to;
    };
    // prepare jqxChart settings
    var settings = {
        title: "Monthly Project Schedule",
        description: "Website update plan",
        enableAnimations: true,
        showLegend: true,
        padding: {
            left: 5,
            top: 5,
            right: 10,
            bottom: 5
        },
        titlePadding: {
            left: 90,
            top: 0,
            right: 0,
            bottom: 10
        },
        source: data,
        xAxis: {
            dataField: 'Person',
            showTickMarks: true,
            tickMarksInterval: 1,
            tickMarksColor: '#888888',
            unitInterval: 1,
            showGridLines: true
        },
        colorScheme: 'scheme03',
        seriesGroups: [{
            orientation: 'horizontal',
            type: 'rangecolumn',
            columnsGapPercent: 100,
  ...