-setTimeout(somefunc, 180000) (three minutes or something reasonable)
-somefunc saves textarea text in an appropriately named cookie that lasts for a few days or more
-somefunc calls setTimeout to start the process over again
-a button named "restore from auto-save" is put on the journal which sets the textarea value to what's in the cookie
This way a computer crash, browser crash, or a random accidental closing of the browser wouldn't wipe out too much information.
The timeout function could also be triggered starting from when someone actually types something into the textbox (instead of when the page is loaded), so people would have time to restore in case they set their autosave to something like 10 seconds.
How feasible is it to add an autosave feature to livejournal?