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Re: Specifying window.performance.now()

From: Boris Zbarsky <bzbarsky@MIT.EDU>
Date: Wed, 29 Feb 2012 16:55:14 -0500
Message-ID: <4F4E9EC2.3080800@mit.edu>
To: James Robinson <jamesr@google.com>
CC: public-web-perf@w3.org
On 2/29/12 4:52 PM, James Robinson wrote:
> Technically speaking using the parameter to track animation progress is
> OK, so long as the page isn't trying to compare the parameter to JS
> Date.now()s.

It's hard to track progress without comparing to "the time I started the 
animation".

And that last is only available via Date.now in most UAs.  :(

> My reading of the code that Google Maps is using for animations today is
> that it's always using the value of Date.now() to update its internal
> progress.

Good!  Well, bad for the actual behavior of the animations, but good for 
making this backwards-incompatible change.  ;)

-Boris
Received on Wednesday, 29 February 2012 21:55:43 GMT

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