.net required field validation (how to turn on/off client side?)

Hi,
I have a page that has the following div:

<div id="divClient2" style="display:none" runat="server" >
    <asp:Label ID="lblClient2" SkinID="form" runat="server">&nbsp</asp:Label>
    <asp:DropDownList ID="ddlTitle2" SkinID="ddlS" runat="server">
    </asp:DropDownList>
    <asp:RequiredFieldValidator ID="valTitle2" runat="server" ControlToValidate="ddlTitle2" Text="*" InitialValue="Title"></asp:RequiredFieldValidator>
    <asp:TextBox ID="txtForename2" SkinID="txtL" runat="server"></asp:TextBox>
    <asp:RequiredFieldValidator ID="valForename2" runat="server" ControlToValidate="txtForename2" InitialValue="firstname" Text="*"></asp:RequiredFieldValidator>    
    <asp:TextBox ID="txtSurname2" SkinID="txtL" runat="server"></asp:TextBox>
    <asp:RequiredFieldValidator ID="valSurname2" runat="server" ControlToValidate="txtSurname2" InitialValue="surname" Text="*"></asp:RequiredFieldValidator>
</div>

As you can see the initial value is dispaly:none and some javascript toggles the div to be displayed or not:

function ShowHide()
{
    var SelectedValue = document.getElementById('<%=ddlClientNumber.ClientID%>').value;
    if(SelectedValue == "2")
    {
        document.getElementById('<%=divClient2.ClientID%>').style.display = 'block';        
    }
    else
    {  
        document.getElementById('<%=divClient2.ClientID%>').style.display = 'none';    
    }        
}

Now, if the div is not displayed, validation is still required on the 3 "hidden" fields, what is the best workaround for this - I would like to validate the field if displayed and not if hidden???

Thanks in advanceStart Free Trial