I've personally always used alt+left to go back. I know backspace does the same thing, but the only reason I know that is because I seem to hit more frequently

I've personally always used alt+left to go back. I know backspace does the same thing, but the only reason I know that is because I seem to hit more frequently than you'd expect while not focused on a form field causing my browser to go back unexpectedly. I've never lost data, though, it always seems to persists when I go forward.