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Time element: Difference between revisions
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<input type="time"> - <time>HH:MM:SS</time> | <input type="time"> - <time>HH:MM:SS</time> | ||
<input type="datetime-local"> - <time>HH:MM:SS-ZZ:YY</time> | <input type="datetime-local"> - <time>HH:MM:SS-ZZ:YY</time> | ||
New proposed [[input]] elements: | |||
<input type="year"> - not supported in current time element | |||
<input type="month-day"> - not supported in current time element | |||
</nowiki></pre> | </nowiki></pre> | ||
In particular the <code><time></code> element is missing support for the following date inputs: | In particular the <code><time></code> element is missing support for the following date inputs: | ||
* input type="month" - this would be satisfied by the [[Time_element#year_month_only| | * input type="month" - this would be satisfied by the [[Time_element#year_month_only|time element year month proposal]]. | ||
* input type="week" - this would be satisfied by the [[Time_element#year_week_only| | * input type="week" - this would be satisfied by the [[Time_element#year_week_only|time element year week proposal]]. | ||
In addition, if the new proposed [[input]] elements are accepted, the respective time element support should be added as well: | |||
* input type="year" - this would be satisfied by the [[Time_element#year_only|time element year proposal]]. | |||
* input type="month-day" - this would be satisfied by the [[Time_element#month_day_only|time element month day proposal]]. | |||
<div class="discussion"> | <div class="discussion"> |
Revision as of 02:10, 6 August 2010
Research, data, use cases, issues, and enhancements related to the HTML5 time
element.
impedance match new date time inputs
The time element should be able to represent every granularity of times and dates that the new date time <input>
elements allow. Here is a list of all the date time <input>
elements along with the corresponding <time>
element usage (if applicable)
<input type="date"> - <time>YYYY-MM-DD</time> <input type="datetime"> - <time>YYYY-MM-DDTHH:MM:SS</time> <input type="month"> - not supported in current time element <input type="week"> - not supported in current time element <input type="time"> - <time>HH:MM:SS</time> <input type="datetime-local"> - <time>HH:MM:SS-ZZ:YY</time> New proposed [[input]] elements: <input type="year"> - not supported in current time element <input type="month-day"> - not supported in current time element
In particular the <time>
element is missing support for the following date inputs:
- input type="month" - this would be satisfied by the time element year month proposal.
- input type="week" - this would be satisfied by the time element year week proposal.
In addition, if the new proposed input elements are accepted, the respective time element support should be added as well:
- input type="year" - this would be satisfied by the time element year proposal.
- input type="month-day" - this would be satisfied by the time element month day proposal.
Opinions / discussion:
- +1 Tantek
- ...
year only
The time element should accept just a year.
- ISO8601 syntax
- YYYY
- use case research
- http://microformats.org/wiki/birthday-examples#year_only
Opinions / discussion:
- +1 Faruk (per Bug 7145 - Valid date strings should accept ambiguous inputs, like "2009" or "2007-01") One example is the very common archive view found on most blogs, which contain distinct links or headers for each year, each month per year, and often each date within a chosen or highlighted month. Currently, the
<time>
element only allows fordatetime
values as precise as a specific day, e.g. YYYY-MM-DD. - -1 Hixie - "Without clear use cases, I don't intend to change the spec here." (ibid)
- +1 Tantek (per HTML5 Super Friends Technical Details: time element)
- +1 Andy Mabbett (Per use cases in VCARDDAV & EDTF - see external links)
- +1 Philip Jägenstedt - for marking up release dates on e.g. MusicBrainz where the date is given as YYYY, YYYY-MM or YYYY-MM-DD.
- ...
year month only
The time element should accept just a year and a month.
- ISO8601 syntax
- YYYY-MM
- use cases
- Blog/publishing archive pages - see Benward.me, ablognotlimited.com (need specific links to archive pages), http://www.flickr.com/photos/tantek/archives/
- output equivalent of
<input type="month">
, see impedance match new date time inputs above.
Opinions / discussion:
- +1 Faruk (per Bug 7145 - Valid date strings should accept ambiguous inputs, like "2009" or "2007-01") One example is the very common archive view found on most blogs, which contain distinct links or headers for each year, each month per year, and often each date within a chosen or highlighted month. Currently, the
<time>
element only allows fordatetime
values as precise as a specific day, e.g. YYYY-MM-DD. - -1 Hixie - "Without clear use cases, I don't intend to change the spec here." (ibid)
- +1 Tantek I think the blog archives use case (where blogs often link to their archives by a specific month and year) is sufficient to justify adding this capability to the time element. Content hosting sites like Flickr also list archives by specific year/month, e.g. see http://www.flickr.com/photos/tantek/archives/
- +1 Andy Mabbett (Per use cases in VCARDDAV & EDTF - see external links)
- +1 Philip Jägenstedt - for marking up release dates on e.g. MusicBrainz where the date is given as YYYY, YYYY-MM or YYYY-MM-DD.
- ...
year week only
The time element should accept just a year and a week number.
- ISO8601 syntax
- YYYY-WNN
- use case research
- no examples in the wild currently. If anyone knows of any sites which publish references to specific weeks of a year, either by name / expression (e.g. "first week of the year") or by specific number (e.g. "weeks 1-26"), please provide URLs and quotes of example content.
- output equivalent of
<input type="week">
, see impedance match new date time inputs above.
- reasoning
- to provide the output equivalent of
<input type="week">
See impedance match new date time inputs above.
Opinions / discussion:
- +1 Tantek per good design of impedance matching date time inputs.
- ...
month day only
The time element should accept just a month and a day.
- ISO8601 syntax
- --MM-DD
- use case research
- http://microformats.org/wiki/birthday-examples#month_and_day_only
Opinions / discussion:
- +1 Tantek (per HTML5 Super Friends Technical Details: time element)
- +1 "radiz" implied support for --MM-DD with the use case question: "How to use <time> with a date in astrology?" in the article http://html5doctor.com/your-questions-answered-6/
- +1 Andy Mabbett (Per use cases discussed in VCARDDAV & EDTF, e.g. birthdays, wedding anniversaries - see external links)
- Portable contacts allows this using a "0000" year value.
Calendar scale
The time element should accept a calendar scale (CALSCALE; default is GREGORIAN) per (and to facilitate interoperability with) the emergent vCard 4 specification, to allow for the the mark-up of non-Gregorian (e.g. Julian) dates, using some as-yet-to-be-formulated CALSCALE type.
Opinions / discussion:
- +1 Andy Mabbett (Per use cases in VCARDDAV, EDTF & TEI - see external links)
- …
Fuzzy dates
The time element should accept fuzzy (uncertain, approximate) dates ("summer 1970", "circa December 1963", "flourished 1580") and eras ("Edwardian", "bronze age", "Jurassic")".
Opinions / discussion:
- +1 Andy Mabbett (Per use cases in "Extended Date Time Format" proposals & TEI - see external links)
- +1 Jim O'Donnell (Dates such as 'circa 1910' published on Flickr eg. The RNVR Training Ship 'Buzzard'… also a list of fuzzy dates for a set of photos.)
Specification ambiguities
The specification requires that time be expressed as UTC (or another time zone with a specified offset from UTC). However, the representation of leap seconds is not specified. Further, the algorithms to convert between string and number are flawed, because the number is described as "number of milliseconds elapsed from midnight UTC on the morning of 1970-01-01" but the actual number of milliseconds includes all kinds of strange decisecond offsets during the period 1961-01-01 to 1972-01-01. Also, UTC did not exist before about 1960.
Unix timekeeping has a long history of terrible definitions, and Unix notions of time should be totally rejected and expunged.
Choose different default date
The statement that valueAsDate IDL attribute should return the value 1970-01-01 plus the appropriate time when the time element contains no date creates a problem that there are likely to be time elements that explicitly contain that date.
A better choice would be a value that is highly unlikely to be encountered, and would be implausible as an actual date in most applications, perhaps 9999-12-31.
Tag
Blog posts, Twitter updates etc. may be tagged HTML5time or #HTML5time
External links
Prior discussion
Resources
- Extended Date Time Format efforts based at the USA's Library of Congress (Covers unspecific dates; date periods and non-Gregorian dates)
- EDTF proposals (use-cases)
- vCard Format Specification draft-ietf-vcarddav-vcardrev-11 (latest draft as at July 2010)
- Section 4.3, date & time
- Section 5.7, CALSCALE (specifies Gregorian or other (e.g. Julian) calendar)
- TEI dates, widely used by archives and libraries to mark up texts, including non-Gregorian ISO8601 & uncertain/ approximate dates
- ISO 8601 (Wikipedia article)