on Submit Button Click Required Field Validator is not working Whn i m using OnClientClick event....

Hello all,
                Ths is my button code:-
<Round:RoundButton ID="SubmitBtn" runat="server" Height="24px" Width="100px" Blend="FromCenterToSurround"                             BorderAlpha="220" BorderAlphaHover="220" BorderColor="#B9E3FF" BorderColorHover="57, 183, 205"                              ...