how can i call on page load if (listitem value 0) then

RadioButtonList button is another page and check different page

<asp:RadioButtonList ID="rlstExport" runat="server">                               

<asp:ListItem Selected="True" Value="0">View in Browser </asp:ListItem>                               

<asp:ListItem Value="1">Export Report to Excel</asp:ListItem>                               

<asp:ListItem Value="2">Export Report to Access</asp:ListItem>                                 

<asp:ListItem Value="2">Export Report to CSV</asp:ListItem>                           

</asp:RadioButtonList>