On Mon, Feb 23, 2015 at 4:57 PM, Simon Fraser <s...@me.com> wrote: > https://html.spec.whatwg.org/multipage/webappapis.html#processing-model-9 > says: > > 1. Let now be the value that would be returned by the Performance object's > now() method > 2. Let docs be the list of Document objects associated with the event loop > in question… > ... > 4. For each fully active Document in docs, run the resize steps for that > Document, passing in now as the timestamp > ... > > This makes no sense, as performance.now() is per-document (it’s relative > to the document start time), so passing the same value to all documents in > the browsing context is bogus. > > What may be intended is to “freeze” the performance.now() time in all > documents before processing those documents, but give each document its own > performance.now() time. >
That is the intent. The algorithm should grab a timestamp for each document "at the same time" (which is really just a matter of grabbing one timestamp and applying the correct offset for each document). - James