<com:TContent ID="Content"> <com:TDatePicker id="test" /> <com:TActiveCustomValidator ID="validator1" ControlToValidate="test" OnServerValidate="ChkDate" ErrorMessage="*"> <prop:ClientSide OnValidationError="$('#error').html('Error')" OnValidationSuccess="$('#error').html('Success')" ObserveChanges="false" /> </com:TActiveCustomValidator> <span id="error"></span> <com:TActiveButton ID="button1" Text="ok"/> </com:TContent>