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Re: How to construct a tomorrow?

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In comp.lang.javascript message <k45dmn$8j7$1@speranza.aioe.org>, Sat,
29 Sep 2012 02:00:31, Christoph Becker <cmbecker69@gmx.de> posted:

>Dr J R Stockton wrote:
>> In comp.lang.javascript message <k401aj$jnh$1@speranza.aioe.org>, Thu,
>> 27 Sep 2012 00:58:35, Christoph Becker <cmbecker69@gmx.de> posted:
>>
>>> justaguy wrote:
>>>> how do we get tomorrow based on today?
>>
>>> So a simple solution is:
>>       xxxxxx naive
>>>
>>> var today = new Date();
>>> var tomorrow = new Date(today.getTime() + 86400000)
>>
>> And what happens when the interval crosses 01:00 UTC on the last Sundays
>> of March and October? (dates and times are different for chronologically
>> inconvenient locations).
>
>I *thought* a day is defined as having 86,400 seconds (cf.
><http://www.bipm.org/en/si/si_brochure/chapter4/table6.html>).  If I am
>mistaken in this view, please correct me -- I'll appreciate an
>explanation or a link to one.

You had one, near enough, in my sig.  The above link refers, manifestly,
to SI days.  Civil days may vary from that by -1, -0.5, +0.5, +1 hours
and also +1 second and -1 second.  The legal UK civil day is still, I
believe, GMT-based, so the +1/-1 second is here in principle replaced by
a rather small fraction of a second.  (Then there are sidereal days,
Martian days, ... )

>If you were referring to summer time issues, AFAIK this wouldn't be
>relevant here, as the calculation is "internal", and the results
>/should/ be faithfully presented in human readable form by calling
>toLocalDateString().

AFAYK != AFAIK.

D1 = new Date("2012 Mar 24 23:30")   // Sat Mar 24 2012 23:30:00
D2 = new Date(D1.getTime() + 864e5)  // Mon Mar 26 2012 00:30:00

D1 = new Date("2012 Oct 28 00:30")   // Sun Oct 28 2012 00:30:00
D2 = new Date(D1.getTime() + 864e5)  // Sun Oct 28 2012 23:30:00

Those not testing in the British Isles may have to adjust the times
and/or the dates - especially any with the OS set for LHI.

JavaScript date work should, wherever practical, be done with the UTC
functions.

-- 
 (c) John Stockton, nr London, UK.    ?@merlyn.demon.co.uk     Turnpike v6.05.
 Website  <http://www.merlyn.demon.co.uk/> - w. FAQish topics, links, acronyms
 PAS EXE etc. : <http://www.merlyn.demon.co.uk/programs/> - see in 00index.htm
 Dates - miscdate.htm estrdate.htm js-dates.htm pas-time.htm critdate.htm etc.

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Thread

How to construct a tomorrow? justaguy <lichunshen84@gmail.com> - 2012-09-26 14:47 -0700
  Re: How to construct a tomorrow? Christoph Becker <cmbecker69@gmx.de> - 2012-09-27 00:58 +0200
    Re: How to construct a tomorrow? justaguy <lichunshen84@gmail.com> - 2012-09-26 17:47 -0700
      Re: How to construct a tomorrow? Gene Wirchenko <genew@ocis.net> - 2012-09-26 19:53 -0700
        Re: How to construct a tomorrow? Dr J R Stockton <reply1239@merlyn.demon.co.uk.invalid> - 2012-09-28 18:40 +0100
          Re: How to construct a tomorrow? Gene Wirchenko <genew@ocis.net> - 2012-09-29 20:52 -0700
    Re: How to construct a tomorrow? Dr J R Stockton <reply1239@merlyn.demon.co.uk.invalid> - 2012-09-28 18:30 +0100
      Re: How to construct a tomorrow? Christoph Becker <cmbecker69@gmx.de> - 2012-09-29 02:00 +0200
        Re: How to construct a tomorrow? John G Harris <john@nospam.demon.co.uk> - 2012-09-29 10:02 +0100
        Re: How to construct a tomorrow? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-09-30 14:29 +0200
          Re: How to construct a tomorrow? Christoph Becker <cmbecker69@gmx.de> - 2012-09-30 23:24 +0200
        Re: How to construct a tomorrow? Dr J R Stockton <reply1239@merlyn.demon.co.uk.invalid> - 2012-09-30 19:55 +0100
  Re: How to construct a tomorrow? Dr J R Stockton <reply1239@merlyn.demon.co.uk.invalid> - 2012-09-27 21:32 +0100
    Re: How to construct a tomorrow? Christoph Becker <cmbecker69@gmx.de> - 2012-09-28 01:03 +0200
      Re: How to construct a tomorrow? Gene Wirchenko <genew@ocis.net> - 2012-09-27 16:36 -0700
      Re: How to construct a tomorrow? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-09-28 10:37 +0200
      Re: How to construct a tomorrow? Dr J R Stockton <reply1239@merlyn.demon.co.uk.invalid> - 2012-09-29 20:39 +0100
        Re: How to construct a tomorrow? Christoph Becker <cmbecker69@gmx.de> - 2012-09-30 23:37 +0200
    Re: How to construct a tomorrow? Andrew Poulos <ap_prog@hotmail.com> - 2012-09-28 09:25 +1000
    Re: How to construct a tomorrow? Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-09-28 08:37 -0700
      Re: How to construct a tomorrow? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-09-28 18:48 +0200
      Re: How to construct a tomorrow? Dr J R Stockton <reply1239@merlyn.demon.co.uk.invalid> - 2012-09-29 20:40 +0100
        Re: How to construct a tomorrow? Andrew Poulos <ap_prog@hotmail.com> - 2012-09-30 18:32 +1000
    Re: How to construct a tomorrow? Eric Bednarz <bednarz@fahr-zur-hoelle.org> - 2012-09-28 23:57 +0200
      Re: How to construct a tomorrow? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-09-30 13:49 +0200

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