Gmail – Does Gmail, Google Docs & Google Calendar Offline work with Offline Storage in Firefox

I currently use Google Gears with Gmail and Google Calendar to keep an offline copy of my mail and calendar. I use Firefox 3.6, but I'm looking at upgrading to Firefox 4.

I read that HTML5 has similar features as Google Gears, and that Google is shifting it's effort to HTML5 instead of Google Gears. On the Google Gears Issue Tracker, issue 1023 also suggests that Google has abandoned Google Gears.

Firefox 4 supports HTML5, and HTML5 supports offline storage. Does Google Mail and Calendar support offline storage with Firefox 4?

Update 7/1/2011:
We're getting there. As @Kaveh points out, Google says they will support Offline Mode in some browsers later this year. However, I don't see Firefox 4/5/6 in that list.

• Gmail now allows you to configure Offline settings at https://mail.google.com/mail/#settings/offline . However, this page says "Offline Mail is not supported by your browser. Learn more." with both Firefox 5, and with Google Chrome 12. At this point, I'm not sure what browser does support Google offline email.
• Google Calendar does not yet have this same 'Offline' option.
• Also see Gmail Help: Gmail › Help articles › Other ways to access Gmail › Offline:

Older updates below.

Update 9/28/2010: I am now running Firefox 4 Beta 6, and there is no option to use DOM Storage or Web Storage with Google Mail, Google Calendar or Google Docs. At least, not out of the box.

According to http://html5test.com/ , Firefox 4 Beta 6 (Running on MacOSX 10.5.8) gets a score of "204 and 9 bonus points out of a total of 300 points". For storage, this browser received the following scores:

> Storage           10/20
> 
> Session Storage   Yes ✔
> Local Storage     Yes ✔
> IndexedDB         No ✘