Fasterfox

Fasterfox.jpg

Fasterfox is a Mozilla Firefox extension that tweaks network connection and caches web pages in order to increase page loading speed.

Optimizations

An interface is provided to adjust a range of networks settings. This allows adjusting of:

  • HTTP pipelining
  • Memory caching
  • Disk caching
  • DNS caching
  • FastBack caching

Prefetching

Fasterfox has the ability to prefetch all links on a page in the background so that when a link is clicked, only a fraction of the time to load the page will be used, since the page has already been cached. Users can disable this option. Fasterfox version 1.0.1 and later checks the robots.txt file on the root folder of servers to see whether or not it should prefetch the page.

Prefetched file types

Firefox can prefetch files with the following extensions:

  • .gif
  • .htm and .html
  • .jpg and .jpeg
  • .pdf
  • .png
  • .txt and .text
  • .xml

Forced Prefetch controversy

Forcing link prefetching, or forcing links which are not specified as prefetchable, is a controversial feature, for many reasons:

  • it is not standards compliant (even though prefetching in itself is a standard)
  • links that might never be viewed are downloaded - with consequences for site statistics
  • this additional traffic costs webmasters additional bandwidth (and therefore money).
  • advertising that is downloaded but not viewed might be morally or even legally problematic (see click fraud).
  • speculative downloading can actually cause cache pollution
  • dynamic content cannot be cached anyway
  • unintended side effects when visiting a web site that ascribes actions to links (i.e. exposing a "Cancel" or "Delete" action via a link)

Web spider

There is an additional issue with automated downloading:

A tool that automatically downloads a set of links is considered a web spider.

  • to satisfy web spider standards, prefetching must at least honour the robots.txt file, which Fasterfox does.
  • a page with a large number of links May Be problematic
  • links with large files may not be desirable

Blocking

As mentioned above, websites can use their robots.txt file to block Fasterfox's user agent from prefetching links to their documents (or to just some of their documents). Many websites do this in order to lower their bandwidth costs.

Pop-Up Blocker

Fasterfox also blocks pop-ups that Appear as a results of Flash plug-ins (movies) and Flash exploits.

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