adding special date to calendar from an array

HTML

<script src="http://jqwidgets.com/jquery-widgets-demo/jqwidgets/globalization/globalize.js"></script>
<link rel="stylesheet" href="http://jqwidgets.com/public/jqwidgets/styles/jqx.base.css">
<script src="http://jqwidgets.com/public/jqwidgets/jqx-all.js"></script>
<div id='jqxWidget'></div>

JavaScript

$(document).ready(function() {
      // Create calendar.
      $("#jqxWidget").jqxCalendar({
        enableTooltips: true,
        width: 220,
        height: 220
      });
      var jsonArray = [{
        "date": new Date("2015-12-20T11:20:00.000Z")
      }, {
        "date": new Date("2015-01-11T09:20:00.000Z")
      }, {
        "date": new Date("2015-02-15T03:20:00.000Z")
      }, {
        "date": new Date("2015-03-21T23:23:00.000Z")
      }, {
        "date": new Date("2015-04-10T11:20:00.000Z")
      }, {
        "date": new Date("2015-06-20T11:20:00.000Z")
      }, {
        "date": new Date("2015-07-20T11:20:00.000Z")
      }, {
        "date": new Date("2015-01-07T11:20:00.000Z")
      }, {
        "date": new Date("2015-01-03T11:20:00.000Z")
      }, {
        "date": new Date("2015-08-20T11:20:00.000Z")
      }, {
        "date": new Date("2015-01-20T11:20:00.000Z")
      }, {
        "date": new Date("2015-10-20T11:20:00.000Z")
      }];
      for (var obj, i = 0; i < jsonArray.length; i++) {
        obj = jsonArray[i];
        $("#jqxWidget").jqxCalendar('addSpecialDate', obj.date, '', 'Special Date');
      }
    });