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[Bug 7868] what about time zones? which one is used? local (may be difficult to find out)? is this communicated to the user? can he change it?

From: <bugzilla@wiggum.w3.org>
Date: Thu, 22 Oct 2009 08:30:45 +0000
To: public-html-bugzilla@w3.org
Message-Id: <E1N0t4H-0006tG-Ix@wiggum.w3.org>

--- Comment #13 from Ian 'Hixie' Hickson <ian@hixie.ch>  2009-10-22 08:30:45 ---
> Please provide an example of an event that has no timezone associated.

All-day events in Google calendar.
Departure dates on sites like Expedia.
Porn sites that ask for birthdays.
Flower delivery sites.
Basically any time a site asks for a date only, and doesn't ask for a time,
they don't want a timezone associated with it.

You haven't provided a single URL to a site contradicting this as far as I can

> Examples of dates with timezone:
> * An all-day event
> I have an all-day meeting or festival in Berlin. It's in the Berlin timezone.
> If I don't specify a timezone, it's the timezone I am in (because most my
> events are geographically near me, for practical purposes). *My* timezone is a
> different timezone from another user, though.

No, in practice, this is incorrect. Calendars have 24-hour-long events
(type=datetime for the start, type=datetime for the end) and day-long events
(type=date). The former have time zone information, the latter do not, and are
displayed somewhere quite different on the display, even when the two users are
in time zones with almost no overlap (e.g. Australia and Hawai'i).

> * My parents are on vacation.
> The timezone my parents are in.
> * A deadline
> Mozilla tree closure at 2009-10-29
> Firefox 3.7 release at 2009-11-20.
> Both are in PDT timezone.

All of the above are examples of precise times, not dates, and one would use
type=datetime, not type=date.

> You still have not responded to the case described in comment 5.

If you want to schedule a reminder, you don't ask for a date, you ask for a

> Other example:
> A calendar site allows to find free time of other users, to schedule events.
> The other user has an all-day event planned. I need to compare my time with the
> all-day event. But I don't know the time zone the latter is in!

In practice, this is not how calendars work as far as I can tell. Certainly,
Google Calendar makes a distinction between all-day events (which are
timezone-less dates) and 24-hour events (two datetimes with timezones).

> If you just WONTFIX all comments that don't match your viewpoint, the spec
> can't improve from other viewpoints!

I am not basing this on my viewpoint. My viewpoint, actually, is that we
shouldn't have time zones at all, and we should all use UTC, and that all data
should be defined relative to UTC, and that the spec therefore should just
define everything as relative to UTC. My viewpoint is irrelevant here.

I'm basing this on use cases.

Please feel free to escalate this if you still disagree.

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