RadDatePicker Invalid Date Alert Box

There is no validator in .net that validate raddatepicker's invalid date. in this case we should use raddatepicker's client event on error.

<telerik:RadDatePicker  runat="server" ID="rdpStartDate">

           <DateInput runat="server">

               <ClientEvents OnError="ValidateDate" />

           </DateInput>

       </telerik:RadDatePicker>

JavaScript

function ValidateDate(sender,args)

{

           var reason = args.get_reason();

           if (reason === 1) 

           {

                alert("Invalid Date");

           }

           if (reason === 2)

           {

               alert("The Date you have typed is out of range");

           }

}