Detect if user Scrolled ASP.Net Panel to Bottom or Top using jQuery

hello,

I have the panel and label. i want page behind code to determine and bind on label whether user is scrolling the panel on upward or downward

<asp:Label ID="lblvalue" runat="server" Text=""></asp:Label>
<asp:Panel ID="Panel1" runat="server" Height="300px">
</asp:Panel>