A couple of months ago I came across Nick Zakas’ YUI approach to this problem, and recently I found Paul Irish’s jQuery plugin which was based on Nick’s work.

This is my attempt at creating a Mootools class that uses the same approach. Quite simply, it fires a timer that activates a callback after a given amount of time. The timer is reset if the user moves the mouse, presses a key, scrolls using the scroll wheel or clicks any mouse button. This has to be done over the active document, obviously.

Key features:

• Can be attached to a single element on the page or the entire document/window.
• Lets you set up multiple instances with different timeouts and events.
• Easily retrieve the idle status from the instance using the isIdle property.
• Find the number of milliseconds since the user was last active.
• Allows you to call the active() method to manually reset the idle state – useful for Flash and other overlays that lets you communicate with Javascript.
• Easily retrieve an IdleTimer instance using element.get(‘idle’, { options });
• Free and open source. MIT-licensed.

Check out the demo page for more details. The source is available on Github as well as in the recently opened MooTools Forge.