A very cute bit of coding. But: I've always wondered who uses these "back to the top" buttons, and why? Until quite recently I hardly ever had reason to go back to the top of the page—I was much more likely to click a link or click the back button—and if I did a quick tap of the home key or flick of the touchscreen usually did the trick. Conveniently, both gestures work even if you've not gotten all the way down to t…
There has never been a technical need for it. The "Home" keyboard button when pressed on a web page has taken you to the top probably since the very first web browser was released. But there's a lot of computer users for whom that entire complex of keys off to the right of Enter on a standard keyboard is The Outer Hinterlands, Where There Be Dragons, except for maybe the arrow keys. Also the entire line of function keys. Not everyone is an expert.