{position: sticky}

It looks like it pins an element in a fixed position when it normal position has scrolled off the screen as long as it's parent container is visible on screen. It displaying it inline as normal when its position is visible onscreen.

It can be used to make sticky-headers like iOS lists have: e.g. showing the letter of the alphabet at the top of the screen when scrolling through an address book .

It will be really useful for keeping the row titles visible in a long scrolling table.