Chrome. Usually web pages behave like you say; unless typing in a "textarea" backspace calls "history.back()". Web developers usually need to manually unbind the keyevent. Given that I couldn't reproduce that, my best guess is that developers did unbind it, but unbinding randomly fails in my computer (and apparently always in yours). Browsers can be capricious. I've installed BackStop though, because I've always find that annoying (web pages used to be static, but now you write a lot and accidental backs are annoying), thanks.