var numberOfCalendarControls = 0;
    var numberToGenerate = 1;
    var controlsHandled = [100];

    function OnEndRequest(sender,args)
            {                            
                 for(var item = 0; item < controlsHandled.length; item++)
                 {
                    controlsHandled[item] = null;
                    numberOfCalendarControls = 0;
                 }
            }
    
    function GenerateCloseButton(sender, e)
    {                   
         var prm = Sys.WebForms.PageRequestManager.getInstance();
            prm.add_endRequest(OnEndRequest);
        //if ($('#ajax__calendar_close_button').length == 0)
       {
        {
            var found = false;
            var lastFoundIndex = 0;
            for(var item = 0; item < controlsHandled.length; item++)
            {
                    if(controlsHandled[item] == sender)
                    {
                        found = true;
                    }
                    if(controlsHandled[item] != null)
                    {
                        lastFoundIndex = item;
                    }
            }
            if(!found)
            {
                controlsHandled[lastFoundIndex + 1] = sender;
                $(sender._header).before("<div class='ajax__calendar_close_button' id='ajax__calendar_close_button" + numberOfCalendarControls + "'>x</div>");
                $('#ajax__calendar_close_button' + numberOfCalendarControls.toString()).bind("click", sender, function(e) {
                    e.data.hide();
                });
                numberOfCalendarControls++;
            }
        }
    }
}