User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8b2) Gecko/20050509 Firefox/1.0+ Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8b2) Gecko/20050509 Firefox/1.0+ Admuncher is a local proxy which modifies the source of the page before it's sent to the browser (it removes banners, etc..). When it modifies the source of the page, bfcache simply does not work at all! This can be tested on http://www.neowin.net. Admuncher can be downloaded from http://admuncher.com/cgi-bin/download.pl/AM-Install.exe (Win32 only). Reproducible: Always Steps to Reproduce: 1. Install Admuncher, start it and enable it. 2. Start Firefox, Enable bfcache, clear the cache, restart firefox 3. Goto http://www.neowin.net 4. Press on any of the articles on top of the page 5. Press Back. Actual Results: Firefox did not use bfcache Expected Results: Firefox should have used bfcache. Firefox does indeed use bfcache if you disable admuncher, clear the cache and re-do steps 3-5.

Is it possible that the proxy modifys the header and FF isn't using the cache at all ?

Here's the header sent to the site with the proxy on: GET / HTTP/1.1 Host: neowin.net User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8b2) Gecko/20050510 Firefox/1.0+ Accept: text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 Accept-Language: en-us,en;q=0.5 Accept-Encoding: gzip,deflate Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7 Keep-Alive: 300 Connection: keep-alive Recieved: HTTP/1.x 200 OK Date: Wed, 11 May 2005 05:30:49 GMT Server: Apache/1.3.33 (Unix) mod_gzip/1.3.26.1a mod_auth_passthrough/1.8 mod_log_bytes/1.2 mod_bwlimited/1.4 PHP/4.3.10 mod_ssl/2.8.22 OpenSSL/0.9.7a X-Powered-By: PHP/4.3.10 Set-Cookie: neolite=deleted; expires=Tue, 11-May-04 05:30:48 GMT Set-Cookie: main_theme=blue; expires=Thu, 11-May-06 05:30:49 GMT; path=/ Set-Cookie: set_id=4; expires=Thu, 11-May-06 05:30:49 GMT; path=/ Connection: close Content-Type: text/html Here are the headers sent to the site with the proxy off: GET / HTTP/1.1 Host: neowin.net User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8b2) Gecko/20050510 Firefox/1.0+ Accept: text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 Accept-Language: en-us,en;q=0.5 Accept-Encoding: gzip,deflate Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7 Keep-Alive: 300 Connection: keep-alive When I add neowin.net to the "Minimal Filtering on URL" cateogry in "My Filters" Admuncher does not insert its javascript helper script, but still removes ads, and in this case bfcache works without problems!

What exact script does admuncher add?

The script varies a bit from page to page because it replaces. The script is pretty long so I don't want to post it here entirely, but here's an excerpt: <script type="text/javascript"><!--// <![CDATA[ // Ad Muncher helper script: do not remove without removing all references to this in the below page (eg: everything containing "yxz" or "yxb") // Original URL: http://fileforum.betanews.com/detail/1032985422/1 // Retrieved from: 140.99.102.70:80 function yxzWdn(){return false;}; function yxzbHelp(a,b){yxzWgp(a);yxzWbn();return;}; function yxzb(a,b,c,d){yxzWgp(a);yxzWbn();return yxzWfw(b);}; function yxzWpp(a){yxzWppa=a;if(a)yxzWorgsti("yxzWppa=0;",500);}; function yxzbtePopup(a,b,c,d,e,f){yxzWgp();yxzWbn();return yxzWfw();}; function yxzbModalDialog(a,b,c){yxzWgp(a);yxzWbn();return yxzWfw();}; function yxzWj(){if(yxzWolp){yxzWqn=yxzWqnbu;yxzWolp=0;};return true;}; Also, HTTPS pages, which Admuncher doesn't insert its helper script into, they work with bfcache too. (like bugzilla) The best way for you to find out is to download AM.. it's harmless.

How about attaching the whole thing as an attachment? The excerpt isn't going to help.

Here's the saved HTML page of http://planet.mozilla.org with AdMuncher being ON (full filtering). Ad Muncher didn't report that it found any banners on the page, but it still inserted its helper script.

That script sets window.onunload.

> The best way for you to find out is to download AM.. it's harmless. fwiw: a) it's win32 only b) people may not like installing random software

This is by design! (scripts using window.unonload are not cached)