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=ISO 8601=
{{DISPLAYTITLE:ISO 8601}}


The '''International Standards Organisation''''s standard, number '''8601''' is an international standard for date and time representations. It is used for all date-time representations in microformats, as well as a number of other formats (XML, XML Schema Datatypes, RDF, Atom).
The '''International Standards Organisation''''s standard, number '''8601''' is an international standard for date and time representations. It is used for all date-time representations in microformats, as well as a number of other formats ([[HTML5]] <code>&lt;time&gt;</code> element &amp; <code>datetime</code> attribute, XML Schema Datatypes, RDF, Atom).
<div style="float: right">https://sslimgs.xkcd.com/comics/iso_8601.png
 
<small style="float: right">Image: [https://xkcd.com/1179/ XKCD]</small>
</div>
In addition, ISO 8601 dates in particular are the most globally unambiguously human readable/writeable date format and thus should always be used on the (world wide) web.


==Overview==
==Overview==
 
The following are good prose overviews of ISO 8601:
For a plain-language overview of ISO 8601, we recommend the [http://www.cl.cam.ac.uk/~mgk25/iso-time.html ISO 8601 summary by Markus Kuhn].
* [http://www.cl.cam.ac.uk/~mgk25/iso-time.html ISO 8601 summary by Markus Kuhn]
* [http://en.wikipedia.org/wiki/ISO_8601 ISO 8601 on Wikipedia]


==Microformats==
==Microformats==
microformats in general use a subset of ISO8601 - preferring uses which are more human readable (requiring hyphens in dates, and colons in times).


Microformats using ISO8601 include:
All date-time properties in microformats use ISO8601 values. E.g.
* all <code>dt-*</code> properties in [[microformats2]]
* all classic microformats's date-time properties, including:
**[[hAtom]] - <code>published</code>, <code>updated</code>
**[[hCalendar]] - <code>dtstart</code>, <code>dtend</code>
**[[hCard]] - <code>bday</code>
**[[hReview]] - <code>dtreviewed</code>


*[[hAtom]]
__TOC__
*[[hCalendar]]
== HTML5 ==
*[[hCard]]
[[HTML5]] uses both a subset of ISO 8601 for dates, times, durations for the <code>&lt;time&gt;</code> element, as well as an extended (and more human friendly) duration format.
*[[hReview]]
*...


==<nowiki>RFC 3339</nowiki>==
==<nowiki>RFC 3339</nowiki>==
Line 23: Line 34:
*It explicitly excludes durations and dates before the [http://en.wikipedia.org/wiki/Common_era common era].
*It explicitly excludes durations and dates before the [http://en.wikipedia.org/wiki/Common_era common era].
*The more complex formats like week numbers and ordinal day are not permitted (see <nowiki>RFC 3339</nowiki>, section 5.6).  
*The more complex formats like week numbers and ordinal day are not permitted (see <nowiki>RFC 3339</nowiki>, section 5.6).  
Microformats {{should}} re-use <nowiki>RFC 3339</nowiki>, but {{must not}} be limited to it, in order to include both more human readable, yet still easily unambiguously parsable, alternatives, as well as ISO 8601 features deemed to be useful.


==ISO 8601 implementations in programming libraries==
==ISO 8601 implementations in programming libraries==
* JodaTime - the Java date-time library - [http://joda-time.sourceforge.net/cal_iso.html ISO8601 Java calendar system]
* JodaTime - the Java date-time library - [http://joda-time.sourceforge.net/cal_iso.html ISO8601 Java calendar system]
* Perl: DateTime::Format::ISO8601
* Perl: DateTime::Format::ISO8601
* Ruby 1.9 implements an iso8601 method in the Date STDLIB but it does not handle ordinal dates.
* Glenn Jones' [https://github.com/glennjones/microformat-node microformat-node] parser includes isodate.js, a Node.js implementation of (some of) ISO 8601.
* Python: [https://pypi.python.org/pypi/iso8601 iso8601]
{{ToDo}} document more implementations.
== FAQ ==
=== Why hyphens in dates ===
Q: Must I use the hyphens?[https://twitter.com/edburns/status/368063860835897344]
A: You <em>should</em> always use hyphens in ISO 8601 dates because that makes them more readable, and thus more human friendly.
Also, using hyphens helps clearly distinguish different uses for different granularities of dates, e.g.:
* 2013-08-19 - just the day
* 2013-08 - the whole month
* 2013 - the entire year


==Issues==
==Issues==
* How should dates before the common era be marked up? [[User:AndyMabbett|Andy Mabbett]]
None currently.
* If a web page is created or edited by a non-technical human, it is unfriendly to expect them to work in ISO date format. [[User:CharlesBelov|Charles Belov]]
 
Resolved issues: [[iso-8601-issues-resolved]].


==See also==
==See also==

Latest revision as of 16:28, 18 July 2020


The International Standards Organisation's standard, number 8601 is an international standard for date and time representations. It is used for all date-time representations in microformats, as well as a number of other formats (HTML5 <time> element & datetime attribute, XML Schema Datatypes, RDF, Atom).

iso_8601.png

Image: XKCD

In addition, ISO 8601 dates in particular are the most globally unambiguously human readable/writeable date format and thus should always be used on the (world wide) web.

Overview

The following are good prose overviews of ISO 8601:

Microformats

microformats in general use a subset of ISO8601 - preferring uses which are more human readable (requiring hyphens in dates, and colons in times).

All date-time properties in microformats use ISO8601 values. E.g.

HTML5

HTML5 uses both a subset of ISO 8601 for dates, times, durations for the <time> element, as well as an extended (and more human friendly) duration format.

RFC 3339

RFC 3339 defines a profile of ISO 8601 for the use in Internet protocols and standards.

  • It explicitly excludes durations and dates before the common era.
  • The more complex formats like week numbers and ordinal day are not permitted (see RFC 3339, section 5.6).

ISO 8601 implementations in programming libraries

  • JodaTime - the Java date-time library - ISO8601 Java calendar system
  • Perl: DateTime::Format::ISO8601
  • Ruby 1.9 implements an iso8601 method in the Date STDLIB but it does not handle ordinal dates.
  • Glenn Jones' microformat-node parser includes isodate.js, a Node.js implementation of (some of) ISO 8601.
  • Python: iso8601

to do! document more implementations.

FAQ

Why hyphens in dates

Q: Must I use the hyphens?[1]

A: You should always use hyphens in ISO 8601 dates because that makes them more readable, and thus more human friendly.

Also, using hyphens helps clearly distinguish different uses for different granularities of dates, e.g.:

  • 2013-08-19 - just the day
  • 2013-08 - the whole month
  • 2013 - the entire year

Issues

None currently.

Resolved issues: iso-8601-issues-resolved.

See also

Related pages

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