I have a website with pages that scroll very far with lots of images on them. Each user that logs in sees a different set of images.
I'd like to record how long the users stay on each portion of the page so I can see which images they're most interested in. For instance, "image 1 stayed visible for 10 seconds", "image 2 stayed visible for 15 seconds", then send these messages back to the server.
What's a good way to do this? Ideally the solution would be able to tell if the image is actually visible, not on a tab that's currently not in the foreground, etc.
Updated: would be great if this includes either a technique that could be used (a little javascript?) or a free tool.