Suggestion: Are you sure you want to leave the page?
I use Google Chrome. I always use the numlock keyboard combinations (ß = 0223, ð = 0240), but my computer automatically turns this off from time to time, and so the key combinations often send me back a couple of pages. Also, I am sure the backspace could anger loads of people, since it automatically goes to the previous page for a lot of browsers. So, what I am asking for is a popup box that asks «Are you sure you wish to leave the page? You are in the middle of a lesson.» and a Yes and No box.