Autosaving of Form Field

HI can anyone suggest a way of autosaving or simulating an autosave function for a specific field in a form.

The story is as follows. I have a bunch of technicians who write notes on how they do a repair. Sometimes they write for a couple of hours the troubleshooting process. If they click incorrectly, press ESC, Cancel or the browser crashes the information is lost which can be heartbreaking so my guys use notepad and then copy the information in. The only way around this is to click submit on the form after 5 minutes and then open the job up again.

I know there is an implementation that will on submit open the form again like a save and reload but this is clumsy. Is there a way of save clicking a little checkbox and this saves that field on the form? or is there a way of doing some scheduled save so that every 2 minutes changes are automatically saved (ideal solution)