[whatwg] ProgressEvents for Images

Boris Zbarsky bzbarsky at MIT.EDU
Thu Feb 23 17:23:18 PST 2012

On 2/23/12 7:38 PM, Hans Muller wrote:
>    Hans - It's useful if you want your listener to run after all of the
> load listeners have run, and code that you haven't written adds its own
> load listeners.

I strongly urge you to read 

Or put another way, what will you do a year after this is standardized, 
when the code that you haven't written is adding loadend listeners?

> The problem with using setTimeout() to schedule a listener to run after
> all of image's load listeners has run is that you've got to guess how long
> loading the image (or failing to load the image) and running its listeners
> will take.

No, you don't.  You simply do:

   function delayedLoadStuff() {
     setTimeout(doTheThingIWant, 0);
   img.addEventListener("load", delayedLoadStuff, false);
   img.addEventListener("error", delayedLoadStuff, false);

> If applications where multiple image load listeners are added by different
> modules really are a rarity (I wouldn't know) then I'll be happy to
> concede that loadend isn't needed.

And they are aren't, then it doesn't help, except in the very short term 
until those modules start using loadend themselves....


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