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Re: [whatwg] 'datetime-local' and 'datetime' comments

From: Mikko Rantalainen <mikko.rantalainen@peda.net>
Date: Tue, 27 Nov 2012 10:39:45 +0200
Message-ID: <50B47C51.40003@peda.net>
To: whatwg@lists.whatwg.org
Nicolas Froidure, 2012-11-13 12:51 (Europe/Helsinki):
> In my opinion, it's normal that datetime and datetime-local have
> timezone and date/time don't. A date is timezone independant and time is
> more a duration then a time relative to a particular instant of a
> particular day.

Unfortunately, "date" is definitely NOT timezone independent. When do
you think "2012-11-28" does start? Some possible "correct choices":

	2012-11-27T16:00:00Z (Googleplex in Mountain View, California)
	2012-11-28T00:00:00Z (UTC)
	2012-11-28T02:00:00Z (Europe/Helsinki, my time zone)
	2012-11-28T11:00:00Z (Ian's time zone, I believe)

Note that all those times are "midnight" in some timezone (and usually
considered official date change in that location). Also note that
"midnight" is happening at some location on earth the very moment you
read this sentence!

I hope that we agree that that date ends about 24 hours (give or take
about one hour if somebody has daylight time change) after the start of
that date.

One would think that we could agree globally on time but normal people
don't even understand the mess that the politicians have created with
timezones and daylight saving time changes.

The problem with absolute time pickers is that there's no way cleanly
fix the issue without normal people understanding the situation. On the
other hand, the problem with non-absolute time pickers is that nobody
really knows what time is meant.

-- 
Mikko
Received on Tuesday, 27 November 2012 08:39:21 GMT

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