In a few minutes we're going to be turning on draft support while updating your journal. This feature automatically saves what you've typed every ten seconds, in both plain and rich text modes. When you successfully post the entry the draft is cleared. If for whatever reason you navigate away from the page, or your browser crashes, when you come back to it you will be prompted to restore from the saved draft. Hitting cancel will clear the draft on the server, as well as deleting everything in the update box will clear the saved draft once the ten seconds have gone by... - via lj_support.