How to maintain tab focus(ajaxtoolkit)

Hi,
I am loading tabs (using ajaxcontrol tookit) dynamically and populating UserControls and inside tabs.
Now, I have only the below code in aspx. How to maintain the tab focus?
<asp:ScriptManager ID="ScriptManager1" runat="server">
    </asp:ScriptManager>
    <asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional">
    </asp:UpdatePanel>
...