How to detect idle time in JavaScript elegantly?

Question

Is it possible to detect \"idle\" time in JavaScript?
My primary use case probably would be to pre-fetch or preload content.

Idle time:

Answer 1

Here is a rough jQuery implementation of tvanfosson's idea:

$(document).ready(function(){

   idleTime = 0;

   //Increment the idle time counter every second.
   var idleInterval = setInterval(timerIncrement, 1000);

   function timerIncrement()
   {
     idleTime++;
     if (idleTime > 2)
     {
       doPreload();
     }
   }

   //Zero the idle timer on mouse movement.
   $(this).mousemove(function(e){
      idleTime = 0;
   });

   function doPreload()
   {
     //Preload images, etc.
   }

})