404 Error Page Status

Feature Description

We want Firefox to override server-supplied 404 error pages in certain cases.  The Firefox 404 page should provide the user with tools we think are more useful to the user for resolving the situation, than the server supplied page.  This includes alternate ("did you mean") URLs derived from the Places database and some pre-loaded search links/controls.


The newest patch is almost ready for review.

This patch is mostly focused on making the code right, but there are a couple of functional changes:
  • The Firefox 404 error page is now pref-controlled.  There's a pref to turn it on and off, and a pref to limit which server-supplied 404 pages we'll override.  Currently we will only override server 404 pages of 512 bytes or less.
  • We're dropping the background image for now.

Next Steps

  • Complete the patch and get it in for review.
  • Blog about it.


  • This feature is being tracked by Bug 482874 - Provide a friendlier/more useful alternative when the user encounters a 404 error page.

Edit: Added Notes section.