how to change the selected date format comes from clndr etdr

Question

how to change the selected date format comes from calendar extender? i need 'mm-dd-yyyy' format.

here's the code:

 

<script language="javascript" type="text/javascript">

function CheckForBackDate(sender, args) {

var selectedDate = new Date();

selectedDate = sender._selectedDate;

var todayDate = new Date();

var grid = document.getElementById("gvDist");

var c = document.getElementsByTagName("table");

// Compare with today date

if (selectedDate.getDateOnly() > todayDate.getDateOnly())

{

sender._selectedDate = todayDate;

sender._textbox.set_Value(sender._selectedDate.format(sender._format));

alert(selectedDate.getDateOnly());

}

} 

 //calling from:

<cc1:CalendarExtender ID="CalendarExtender2" runat="server" TargetControlID="txtCloseDate"

OnClientDateSelectionChanged ="CheckForBackDate"

OnClientShown="ChangeCalendarView" PopupButtonID="imgStartDate" Format="MM-dd-yyyy" >