Hi,
I am using RadDatePicker and have written the below given java script function to handle OnError event.
Now if I enter 505050 as the input i am getting the error "Enter a Valid Date in YYYY/MM/DD Format" multiple times if I press the "Enter" key to close the alert dialog which is very annoying. 
I am new to ASP.NET as well as Telerik controls. Please let me know what is going wrong.

ASPX
<telerik:RadDatePicker ID="dtmFromDt" runat="server" Width="100px"
   Visible="true" MinDate="1500/01/01" MaxDate="3000/01/01" DateInput-DateFormat="yyyy/MM/dd"                                                     Skin="WebBlue">
        <ClientEvents OnPopupClosing="OnPopupClosing"/>
<DateInput  runat="server" EmptyMessage="YYYY/MM/DD" Visible="true" ClientEvents-OnError="ShowDateError" >                     </DateInput>
<Calendar Skin="WebBlue" runat="server" UseColumnHeadersAsSelectors="False" UseRowHeadersAsSelectors="False"                                                    ViewSelectorText="x">
</Calendar><DatePopupButton HoverImageUrl="" ImageUrl="" />
</telerik:RadDatePicker>
JavaScript 
function ShowDateError(sender, args)  
{  
alert ("Enter a Valid Date in YYYY/MM/DD Format");  
sender.focus();   
return false;
}

Please find attached image of code from a sample solution

Regards,
Murthy Meka

Hi Murthy,

This issue is fixed in newer RadControls versions. In your case you can use a global Javascript variable as a flag to prevent multiple alerts from appearing.

Kind regards,
Dimo
the Telerik team