Date format issue while retriveing it form database into datatable

Question

I am trying to retrieve the dates from database into datatable but I am getting the below problem. your help will be highly appreciated.

\/Date(1239018869048)\/

Error

Controller:

  public ActionResult GetData()
    {

        List<LeavePeriod> leavindb = _dbContext.LeavePeriod.ToList<LeavePeriod>();
        return Json(new { data = leavindb }, JsonRequestBehavior.AllowGet);
    }

view:

@section scripts
  {


   <script>
    var Popup, dataTable;
    $(document).ready(function () {

        dataTable = $('#leaveperiod').DataTable({
            "ajax": {
                "url": "/LeaveSetup/GetData",
                "type": "GET",
                "datatype": "json"
            },
            "columns": [
                //{ "data": "LeavePeriodId" },
                {
                    "data":"StartDate"

                },
                { "data": "EndDate" },

                {
                    "data": "LeavePeriodId",
                    "render": function(data) {
                        return "<a class='btn btn-default btn-sm' onclick=PopupForm('@Url.Action("AddOrEdit", "LeaveSetup")/" +data +"')><i class='fa fa-pencil'></i> Edit</a>" +"<a class='btn btn-danger  btn-sm'style='margin-left:5px;'onclick=Delete(" +data +") ><i class='fa fa-trash'></> Delete</a>";
                    },
                    "orderable": false,
                    "searchable": false,
                    "width": "120px"
                }
            ]
        //    ,
        //    "language": { "emptyTable": "No data found,Please click on <b>Add New</b> Button" }
        });
    });

    function PopupForm(url) {

        var formDiv = $('<div/>');
        $.get(url)
            .done(function (response) {
                //start here

                //end
                formDiv.html(response);
                Popup = formDiv.dialog({
                    autoOpen: true,
                    resizable: false,
                    title: 'Fill LeavePeriod Details',
                    height: 500,
                    width: 700,
                    close: function () {
                        Popup.dialog('destroy').remove();
                    }
                });
            });
    }


</script>

}