I am trying to compare start date and end date in jquery. Code in aspx page looks like:

<asp:TextBox ID=tbStartDate runat=server CssClass=textbox Width=80px contentEditable=false onchange=javascript:compareDates();></asp:TextBox>



<asp:ImageButton runat=Server ID=ibStartCalendar ImageUrl=~/Images/calendar.jpg

 Height=18px AlternateText=Click to show calendar />



<act:CalendarExtender ID=ceStartDate  runat=server Format=dd-MMM-yyyy TargetControlID=tbStartDate PopupButtonID=ibStartCalendar CssClass=Calendar>

</act:CalendarExtender>

And javascript function:

function compareDates() {

  var start = $(#<%=tbStartDate.ClientID %>).val();

  var end = $(#<%=tbEndDate.ClientID %>).val();



  if (!compareDate(start, end)) { 

$(#<%=lblMsg.ClientID %>).html(Start Date can not be greater than End Date);

                    }

  }

 function compareDate(start, end) {

    if (start.length > 0 && end.length > 0) {

        var stDate = new Date(start);

        var enDate = new Date(end);

        var compDate = enDate - stDate;



        if (compDate >= 0)

            return true;

        else {

            return false;

        }

    } else { return true; }

}

Requirement is to dispaly date in dd-MMM-yyyy format in text boxes to I can not change format in calenderExtender.

When I keep this format star date and end date becomes NaN. If I change format in calenderExtender i get proper results. However as I said I can not change format there. How can I change format in javascript?