The icecore:idleMonitor renders the enclosed markup when the user has not interacted with the page for a defined period of time. The rendered markup is hidden when user resumes the activity. In this example you need to stop using the page for 10 seconds in order to see the warning.

Note that a space delimited string of events can be defined to listen for inactivity and that default events are "keydown mouseover". "keypress mouseover" are used in this example.