We have noticed a problem on our site related to cookie handling and the Firefox (version 19.0.2) and Chrome (version 25.0.1364.172 m) and the cookies generated by the EU cookie plugin required to meet EU regulations.
The problem, which is (we believe) caused by the use of the Joomla system (page) cache manifest itself either as no EU message being displayed, to enable acceptance of the cookie, or as the cookie acceptance appearing to be ignored (even though it has been accepted) and the message continuing to be displayed. Option changes to the system cache plugin do not make any difference.
Not a show stopper but a problem none the less. The problem although first noticed on our own site is also evident on other sites complying with the EU regulations and using cookies.
The problem relates to the caching that is being carried out, either in the Joomla system, and/or the browser itself. One option might be to clear the system cache when a cookie is accepted, so that any cached pages are flushed, but the downside of this is that there may/will be a consequence of flushing the cache regularly on busy sites. Simply forcing the page to be reloaded from the system is not sufficent when the cache is in the system.
There appears to be four possible options:
1. Change EU cookie plugin being used to one where the cache is handled correctly.
2. Disable the Joomla system (page) cache plugin.
3. Use a different page cache product.
4. Alter the EU cookie plugin code to add a flush of the cache.
Initially we have taken option 2, and modified the EU plugin to display the Cookie message at the bottom of the page rather than the top so that the top menu is not obscured.
Updated 20/03/2013: Installed JOTcache (option 3) which enables one to have separate cache pages depending upon the cookie settings, and seems to have restored the page loading times and is handling the cookie correctly.
Aside: This is not a browser problem per sec, however we have discovered problems with the Firefox (19.0.2) browser where we have noticed some very long periods when a page is being loaded, and also periodic crashes of the browser for no apparent reason that we can determine. These problems do not occur with earlier Firefox versions, Opera (12.14) or with the Chrome browser (version 25.0.1364.172 m).