After user clicks on postback controls, ASP.NET web page is reloaded in
the browser and scroll position is set to the top of the page.
If your pages are high/long and controls that cause postback are placed
on the bottom it can be really annoying for users to manually scroll
down after every postback.
Fortunately, this can be easily solved using the Page.MaintainScrollPositionOnPostBack property like this:
<%@ Page Language="C#" AutoEventWireup="true" ... MaintainScrollPositionOnPostback="true" %>
After the postback and reload of the page, the previous scroll position will be restored.
NOTE: This only works in .Net Framework 2.0 and higher!