<asp:Panel ID="Panel1" runat="server" Height="101px">
    Day
    <asp:DropDownList ID="DropDownList1" runat="server" Height="24px" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged">
    </asp:DropDownList>
    &nbsp;Hour
    <asp:DropDownList ID="DropDownList2" runat="server">
    </asp:DropDownList>
</asp:Panel>

<div>
    Day
    <asp:DropDownList ID="DropDownList1" runat="server">
    </asp:DropDownList>
    Hour
    <asp:DropDownList ID="DropDownList2" runat="server">
    </asp:DropDownList>
</div>