During a page postback, the page is redrawn by default and users see a short but annoying flickering. Worse, the scroll position isn't preserved during postbacks (the page scrolls to its top) and the first control on the page takes the input focus. This behavior contrasts with the experience that users have with regular Windows applications and tends to be confusing.
If you're working with Internet Exporer 5.0 or a later version, you can overcome all these shortcomings by setting the SmartNavigation property to True, which performs the following tasks:
Eliminates the flashing that usually occurs when a page is reloaded.
Preserves the scroll position in longer pages.
Maintains the input focus between postbacks.
Retains only the last page state in the browser's history.
This property is especially useful for forms that do a lot of postbacks but whose contents don