A third example of a common use of these concepts is a web browser that can be instructed to be in either online or offline states. The browser only attempts to fetch pages from servers whilst in the online state. In the offline state, users can perform offline browsing, where pages can be browsed using local copies of those pages that have previously been downloaded whilst in the on-line state.
This can be useful when the computer is offline and connection to the Internet is impossible or undesirable. The pages are either downloaded implicitly into the web browser's own cache as a result of prior online browsing by the user, or explicitly by a browser configured to keep local copies of certain web pages, which are updated when the browser is in the online state, either by checking that the local copies are up-to-date at regular intervals or by checking that the local copies are up-to-date whenever the browser is switched to the on-line state. One such web browser capable of being explicitly configured to download pages for offline browsing is Internet Explorer. When pages are added to the Favourites list, they can be marked to be "available for offline browsing". Internet Explorer will download to local copies both the marked page and, optionally, all of the pages that it links to. In Internet Explorer version 6, the level of direct and indirect links, the maximum amount of local disc space allowed to be consumed, and the schedule on which local copies are checked to see whether they are up-to-date, are configurable for each individual Favourites entry.
Offline browsing known as "Offline favourites" was removed as a feature in Internet Explorer 7, which now only supports saving single web pages, but not an entire site.