Ifvisible.js – Check if User is Idle or Active on the Page

ifvisible.js is a crosbrowser & lightweight way to check if user is looking at the page or interacting with it. It can handle activity states too, such as being IDLE or ACTIVE on the page. You can manually trigger status events by calling them directly or you can set events with their names by giving first argument as a callback. You can also set your smart intervals with ifvisible.js, if user is IDLE or not seeing the page the interval will automatically stop itself.

Requirements: JavaScript Framework
Demo: http://serkanyersen.github.com/ifvisible.js/demo.html
License: License Free