Im getting above runtime error on 

OnClientDateSelectionChanged="ValidateDate" of CalendarExtender

Code:

<%

here i'm checking with today's date... check this...

<script type="text/javascript">

        function checkDate(sender, args) {
            if (sender._selectedDate < new Date()) {
                alert("You cannot select a day earlier than today!");
                sender._selectedDate = new Date();
                // set the date back to the current date
               sender._textbox.set_Value(sender._selectedDate.format(sender._format))
                 //var text=document.getElementById('txtClosingDate');
                 //text.value=null;
            }
        }

    </script>

<cc1:CalendarExtender ID="CalendarExtender1" runat="server" TargetControlID="txtOpenDate"
        OnClientDateSelectionChanged="checkDate" PopupPosition="Right" PopupButtonID="Image3">
                </cc1:CalendarExtender>

call check date function in OnClientDateSelectionChanged event

Im also calling the required function in OnClientDateSelectionChange event 

But it throwing error in running the project that runtime error related to Microsoft JScript runtime.

It is not linked with funtion code as also tried with simple funtion with only alert actually it is not entertaining any funtion on this event.

Hi,

If you define OnClientDateSelection event "OnClientDateSelection='ValidateDate'", you can define the javascript function in the tail of the html page.

function ValidateDate(arg,e)
{
    //
}