Alternative to setInterval && setTimeout

javascript's setTimeout and setInterval are evil and not precise...

1. both have a delay of various milliseconds http://www.andrewduthie.com/post/a-self-correcting-setinterval-alternative/

2. both are very resource intensive as they execute several times every second.

A new alternative is requestAnimationFrame. it's less resourceintensive, does not slow down other stuff & it is disabled on page blur.

This makes it the perfect sobstitue for a modern setTimeout & setInterval.

So i wrote this functions:

Description

This functions use requestAnimationframe to check if the time is passed based on the elapsed Time calculated from Date.now. The time passed is more precise than the native functions & theroretically less resource intensive. Another advantage/disadvantage(depends) is that the functions are not executed on page blur. ...

Good for: animations, visual effects

Bad for: timers, clock....

RafTimeout

window.rtimeOut=function(callback,delay){
 var dateNow=Date.now,
     requestAnimation=window.requestAnimationFrame,
     start=dateNow(),
     stop,
     timeoutFunc=function(){
      dateNow()-start<delay?stop||requestAnimation(timeoutFunc):callback()
     };
 requestAnimation(timeoutFunc);
 return{
  clear:function(){stop=1}
 }
}

RafInterval

window.rInterval=function(callback,delay){
 var dateNow=Date.now,
     requestAnimation=window.requestAnimationFrame,
     start=dateNow(),
     stop,
     intervalFunc=function(){
      dateNow()-start<delay||(start+=delay,callback());
      stop||requestAnimation(intervalFunc)
     }
 requestAnimation(intervalFunc);
 return{
  clear:function(){stop=1}
 }
}

Usage

var interval1,timeout1;
window.onload=function(){
 interval1=window.rInterval(function(){console.log('interval1')},2000);
 timeout1=window.rtimeOut(function(){console.log('timeout1')},5000);
}

/* to clear
interval1.clear();
timeout1.clear();
*/

Demo

http://jsfiddle.net/wZ9Z6/

QUESTIONS

1. Normally i don't write functions inside functions, but in this case it's prolly a good solution. What about memory leaks if i create hundreds of this timebased functions?

2. Is there a better solution to clear those functions?

3. For heavy animations and multiple intervals,timeouts i was thinking to activate a single requestAnimationFrame loop which check for intervlas and timeouts inside a previously stored array... (but i think there should be no difference if there are just one requestAnimationframe or multiple). So how do the browsers handle those multiple requestAnimationframes?

Note:

if the code above does not work here is the original code.

window.rInterval=function(a,b){var c=Date.now,d=window.requestAnimationFrame,e=c(),f,g=function(){c()-e<b||(e+=b,a());f||d(g)};d(g);return{clear:function(){f=1}}}//callback,delay
window.rtimeOut=function(a,b){var c=Date.now,d=window.requestAnimationFrame,e=c(),f,g=function(){c()-e<b?f||d(g):a()};d(g);return{clear:function(){f=1}}}