Question

I’m having a setTimeout problem similar to this one. But that solution doesn’t help me since I can’t use php in my file.

My site has a slider with a list of images that move every 8 seconds.However, when I have opened a few tabs in the browser and then switch back again, it goes nuts.
The slider proceeds to move the images one after the other immediately without the 8 second timedelay.

I’m only seeing it in Chrome and the latest Firefox.

**EDIT: I checked with console.log() and the setTimeout returns the same number before and after the clearTimeout. Not sure why. Maybe that also has something to do with it? **

EDIT 2: I added a fiddle: http://jsfiddle.net/Rembrand/qHGAq/8/

The code looks something like:

spotlight: {
    i: 0,
   timeOutSpotlight: null,

   init: function()
   {
       $('#spotlight .controls a').click(function(e) {

           // do stuff here to count and move images

           // Don't follow the link
           e.preventDefault();

           // Clear timeout
           clearTimeout(spotlight.timeOutSpotlight);

           // Some stuff here to calculate next item

           // Call next spotlight in 8 seconds
           spotlight.timeOutSpotlight = setTimeout(function () {
                spotlight.animate(spotlight.i);
            }, 8000);
       });

       // Select first item
       $('#spotlight .controls a.next:first').trigger('click');
   },

   animate: function(i)
   {
       $('#spotlight .controls li:eq(' + (spotlight.i) + ') a.next').trigger('click');
   }
}

Answer 1

From the jQuery documentation:

Because of the nature of requestAnimationFrame(), you should never
queue animations using a setInterval or setTimeout loop. In order to
preserve CPU resources, browsers that support requestAnimationFrame
will not update animations when the window/tab is not displayed. If
you continue to queue animations via setInterval or setTimeout while
animation is paused, all of the queued animations will begin playing
when the window/tab regains focus. To avoid this potential problem,
use the callback of your last animation in the loop, or append a
function to the elements .queue() to set the timeout to start the next
animation.