"How do you show the current position in a document for which, for one reason or another, you cannot instantly compute the visible height? " Actually, that sou

"How do you show the current position in a document for which, for one reason or another, you cannot instantly compute the visible height? " Actually, that sounds like an idea, make the height of the page roughly the real height of the total pages. It can still load content on scroll, but being able to leap ahead a few pages sounds great. Now if we can just get it to remember our position when we hit back, and not just return us to the beginning of the adventure, then infinite scroll would be tolerable.