Hello,
When using Google Reader and browsing RSS entries in the "Expanded" view, entries will automatically be marked as 'read' once a certain percentage of the div is visible on the screen (difficult to tell what percentage has to be visible in the case of Google Reader). So, as I scroll down line-by-line, the javascript code can determine that a) the entry is being rendered in the visible window and b) a certain amount is visible and when those conditions are met, the state is toggled to read.
Does anyone have any idea how that feature is implemented? Specifically, does anyone here know how to tell if a div has scrolled into view an how much of the div is visible?
As an aside, I'm using jQuery, so if anyone has any jQuery-specific examples, they would be much appreciated.
Thanks in advance,
Scott