Want to quickly see how many unread messages you have in Gmail?  Well, with a little help from Firefox, Gmail and one creative userscript author, that can easily be done.  Gmail FavIcon Alerts 3 adds an unread message counter to the Gmail favicon in your browser.

Along with the unread message count, you also get a red Gmail icon when there is no unread messages:

…and a chat bubble when somebody is trying to chat with you via Gmail:

Here are a few more things new in this version 3 of Gmail FavIcon Alerts:

Now, you can keep tabs on the exact number of unread messages you have! With the power of the <canvas> tag, the unread message count is now dynamically created for your number of unread messages. The font scales well up to 999 unread messages, but higher numbers are still rendered for those with massive unread counts.

If you have Greasemonkey installed, to get this userscript – just head on over to Userscripts.org and hit “Install”.  Gmail FavIcon Alerts 3 is well worth using, if you spend a lot of time in your Gmail inbox.