[whatwg] Dates and coordinates in HTML5

WeBMartians webmartians at verizon.net
Tue Feb 24 17:55:25 PST 2009

I think the problem with ISO-8601(:2004?) is that while it is precise, total support requires a large code footprint and effort
(durations, intervals, compressed formats and so on). I seem to remember that there is some kind of conflict with something in
Javascript regarding years that are represented by strings of more than four characters: years preceding 999 BCE (or 1000 BCE?) or
subsequent to 9999 CE.
-----Original Message-----
From: David Singer [mailto:singer at apple.com] 
Sent: Tuesday, 2009 February 24 15:12
To: WeBMartians; 'Andy Mabbett'; 'WHATWG List'
Subject: Re: [whatwg] Dates and coordinates in HTML5

At 13:59  -0500 24/02/09, WeBMartians wrote:
>It's back! It won't die! :-)
>Although it can be argued that a standard should not consider the work 
>required for implementation, many of the trade-offs in reference to 
>times and dates do indeed take the present state of code into 
>One reason for not supporting BCE is a disagreement between historians 
>and, say, astronomers, on how to represent the year immediately 
>preceding year one. Is it year -1 (1 BCE) or year zero?
>Currently, the text states that all dates and times since the beginning 
>of the common era (0001-01-01 00:00:00Z) must be supported. Yes, the 
>Javascript values can specify dates and times before this epoch. 
>However, there is no way to interrogate the environment as to whether 
>or not such values can be used with <time>. That would require much 
>more work. Thus, the limitation of common era.
>I'd love to see support for BCE and even for prolepsis and 
>non-Gregorian calendars. ...but I do see the "no BCE" compromise as a 
>workable one.

ISO 8601 is quite precise on this issue.  Since these are both machine and human-readable, why is this precision a problem?

Why would we not use ISO 6709 (Annex H, text string) as the format for location?

David Singer
Multimedia Standards, Apple Inc.

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