whenever div is visble not required validation

Hi Friends
My problem is i am hiding the some fields using did visible fals property
whenever div is visible true the validation is working fine the problem is even hiding validation is working
my cod ebelow
 <div id="Ratediv" runat="server" visible="false">             <tr >                               <td>                      <asp:Label ID="lblRateCard" runat="server" CssClass="forLabel" Text="Rate in Original Currency(per day)"></asp:Label>               &n ...