[webkit-dev] Adding high resolution platform timestamp to DOM events

[Ryosuke Niwa]

As Elliott pointed out, this property doesn't seem to be on any working
draft or editor's draft yet. And it doesn't seem like either thread on
www-dom or www-perf reached a consensus.

I'd appreciate if you waited until either thread reached a rough consensus
about the feature. Namely, www-dom thread discussion leads me to believe
that some people think we can simply modify timeStamp IDL attribute instead
of adding new one.

- Ryosuke

On Wed, Oct 24, 2012 at 6:17 PM, Robert Flack <flackr at chromium.org> wrote:

> Hi webkit-dev,
>
> I would like to add platform timestamps to DOM events as the systemTime
> property. I have a patch implementing the feature:
> https://bugs.webkit.org/show_bug.cgi?id=94987. This will let us know the
> time at which the system received an event to be able to accurately handle
> it, whereas the timestamp property gives the time the DOM event was created
> in an inaccurate milliseconds since 1970 form. This has been discussed on
> www-dom (http://lists.w3.org/Archives/Public/www-dom/2012OctDec/0028.html)
> and www-perf (
> http://lists.w3.org/Archives/Public/public-web-perf/2012Oct/0046.html)
> and use cases for this have been discussed (
> http://lists.w3.org/Archives/Public/www-dom/2012AprJun/0092.html).
>
> The platform timestamp comes in as a monotonic timestamp. Since the DOM
> Event spec requires that timeStamp() be a 1970-epoch based timestamp it is
> not sufficient for a high resolution precise time delta on event delivery.
> Instead, we add a systemTime property which uses the Performance API spec (
> http://dvcs.w3.org/hg/webperf/raw-file/tip/specs/HighResolutionTime/Overview.html)
> for high res timestamps (time since document load timestamp to avoid user
> fingerprinting) and provide the platform's high resolution timestamp to
> ECMAScript.
>
> Let me know if you have any suggestions. I look forward to everyone's
> feedback, cheers!
> - Rob
>
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>
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