[whatwg] A better animation API

Boris Zbarsky bzbarsky at MIT.EDU
Sat Dec 10 00:13:57 PST 2011

On 12/10/11 3:11 AM, Boris Zbarsky wrote:
> On 12/10/11 2:55 AM, Robert Eisele wrote:
>> It's certainly also more difficult to implement but asking for every
>> frame
>> to continue has also the disadvantage of beeing as slow as setting up
>> a new
>> timeout for every frame. That's why setInterval surpass setTimeout's
>> performance (okay, at least it should).
> In theory, yes.

One other note.

The principal practical difference between setInterval and setTimeout 
(other than all the pages that setInterval something and then forget to 
cancel it) is their handling of delays in firing times.  With 
setInterval you can get a more uniformly firing timer, because if one 
firing gets delayed the next one might compensate.  With setTimeout the 
only way to get that behavior is to manually compensate by comparing the 
actual firing time to the desired one and adjusting the argument to the 
next setTimeout call accordingly.

With requestAnimationFrame, of course, the firing time thing is a 
non-issue, because you're not scheduling a callback for a particular 
time in the first place.


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