Opera has the ability to restore text typed in an online form or in a reply box on blogs or discussion board, even after you have moved away from the page. Just hit the back button and presto, all that you typed are still there. This is immensely useful in situations where the connection goes dead the moment you click the send button or the server was busy and the data couldn’t go through. You don’t have to type again.
But Opera cannot recover typed text if you close the tab and then restore it. This time the text is gone. This also happens when Opera crashes. This shortcoming can be fixed with the Persistent Text Opera extension.
With Persistent Text installed Opera remembers the text you entered in a web form when you reopen a tab after closing it, or if Opera unexpectedly crashes. I can’t vouch how Opera will react after a crash, but it indeed recovers the data from reopened tabs.
The extension stores all data locally on your hard drive (exactly where, I’m not sure) and restores it from there. From the extension's preferences you can turn on a confirmation prompt that will appear before it try to restores the data. On the same page, you can also see a list of stored data and selectively purge the ones not needed.
Firefox users looking for a similar feature can install Lazarus.