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[e] (0) Add more commentary on time zones.
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Fixing https://www.w3.org/Bugs/Public/show_bug.cgi?id=17857
Affected topics: HTML

git-svn-id: http://svn.whatwg.org/webapps@7733 340c8d12-0b0e-0410-8428-c7bf67bfef74
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Hixie committed Mar 6, 2013
1 parent 333ce86 commit 3ee72b2
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30 changes: 29 additions & 1 deletion complete.html
Expand Up @@ -19844,6 +19844,13 @@ <h4 id=the-time-element><span class=secno>4.6.11 </span>The <dfn><code>time</cod
<pre class=example>&lt;time&gt;2011-11-12 14:54:39&lt;/time&gt;</pre>
<pre class=example>&lt;time&gt;2011-11-12 14:54:39.929&lt;/time&gt;</pre>

<p class=note>Times with dates but without a time zone offset are useful for specifying events
that are observed at the same specific time in each time zone, throughout a day. For example,
the 2020 new year is celebrated at 2020-01-01 00:00 in each time zone, not at the same precise
moment across all time zones. For events that occur at the same time across all time zones, for
example a videoconference meeting, a <a href=#valid-global-date-and-time-string>valid global date and time string</a> is likely
more useful.</p>

</dd>


Expand All @@ -19857,6 +19864,12 @@ <h4 id=the-time-element><span class=secno>4.6.11 </span>The <dfn><code>time</cod
<pre class=example>&lt;time&gt;-0800&lt;/time&gt;</pre>
<pre class=example>&lt;time&gt;-08:00&lt;/time&gt;</pre>

<p class=note>For times without dates (or times referring to events that recur on multiple
dates), specifying the geographic location that controls the time is usually more useful than
specifying a time zone offset, because geographic locations change time zone offsets with
daylight savings time. In some cases, geographic locations even change time zone, e.g. when the
boundaries of those time zones are redrawn, as happened with Samoa at the end of 2011.</p>

</dd>


Expand Down Expand Up @@ -19904,6 +19917,14 @@ <h4 id=the-time-element><span class=secno>4.6.11 </span>The <dfn><code>time</cod
<pre class=example>&lt;time&gt;2011-11-12 06:54:39-08:00&lt;/time&gt;</pre>
<pre class=example>&lt;time&gt;2011-11-12 06:54:39.929-08:00&lt;/time&gt;</pre>

<p class=note>Times with dates and a time zone offset are useful for specifying specific
events, or recurring virtual events where the time is not anchored to a specific geographic
location. For example, the precise time of an asteroid impact, or a particular meeting in a
series of meetings held at 1400 UTC every day, regardless of whether any particular part of the
world is observing daylight savings time or not. For events where the precise time varies by the
local time zone offset of a specific geographic location, a <a href=#valid-local-date-and-time-string>valid local date and time
string</a> combined with that geographic location is likely more useful.</p>

</dd>


Expand Down Expand Up @@ -46088,7 +46109,7 @@ <h4 id=the-input-element><span class=secno>4.10.7 </span>The <dfn><code>input</c
<td class=no> &middot; <!-- Reset Button -->
<!-- <td class="no"> &middot; Button -->

</table><div class=impl>
</table><!--CLEANUP--><div class=impl>

<p>Some states of the <code title=attr-input-type><a href=#attr-input-type>type</a></code>
attribute define a <dfn id=value-sanitization-algorithm>value sanitization algorithm</dfn>.</p>
Expand Down Expand Up @@ -47303,6 +47324,13 @@ <h6 id="date-and-time-state-(type=datetime)"><span class=secno>4.10.7.1.7 </span
instead, the calendar application would have also had to explicitly
determine which time zone the user intended.</p>

<p>For events where the precise time is to vary as the user travels (e.g. "celebrate the new
year!"), and for recurring events that are to stay at the same time for a specific geographic
location even though that location may go in and out of daylight savings time (e.g. "bring the
kid to school"), the <code title=attr-input-type-datetime-local><a href="#local-date-and-time-state-(type=datetime-local)">datetime-local</a></code> type
combined with a <code><a href=#the-select-element>select</a></code> element (or other similar control) to pick the specific
geographic location to which to anchor the time would be more appropriate.</p>

</div>


Expand Down
30 changes: 29 additions & 1 deletion index
Expand Up @@ -19844,6 +19844,13 @@ this specification: the &lt;abbr&gt;WHATWG&lt;/abbr&gt; and the
<pre class=example>&lt;time&gt;2011-11-12 14:54:39&lt;/time&gt;</pre>
<pre class=example>&lt;time&gt;2011-11-12 14:54:39.929&lt;/time&gt;</pre>

<p class=note>Times with dates but without a time zone offset are useful for specifying events
that are observed at the same specific time in each time zone, throughout a day. For example,
the 2020 new year is celebrated at 2020-01-01 00:00 in each time zone, not at the same precise
moment across all time zones. For events that occur at the same time across all time zones, for
example a videoconference meeting, a <a href=#valid-global-date-and-time-string>valid global date and time string</a> is likely
more useful.</p>

</dd>


Expand All @@ -19857,6 +19864,12 @@ this specification: the &lt;abbr&gt;WHATWG&lt;/abbr&gt; and the
<pre class=example>&lt;time&gt;-0800&lt;/time&gt;</pre>
<pre class=example>&lt;time&gt;-08:00&lt;/time&gt;</pre>

<p class=note>For times without dates (or times referring to events that recur on multiple
dates), specifying the geographic location that controls the time is usually more useful than
specifying a time zone offset, because geographic locations change time zone offsets with
daylight savings time. In some cases, geographic locations even change time zone, e.g. when the
boundaries of those time zones are redrawn, as happened with Samoa at the end of 2011.</p>

</dd>


Expand Down Expand Up @@ -19904,6 +19917,14 @@ this specification: the &lt;abbr&gt;WHATWG&lt;/abbr&gt; and the
<pre class=example>&lt;time&gt;2011-11-12 06:54:39-08:00&lt;/time&gt;</pre>
<pre class=example>&lt;time&gt;2011-11-12 06:54:39.929-08:00&lt;/time&gt;</pre>

<p class=note>Times with dates and a time zone offset are useful for specifying specific
events, or recurring virtual events where the time is not anchored to a specific geographic
location. For example, the precise time of an asteroid impact, or a particular meeting in a
series of meetings held at 1400 UTC every day, regardless of whether any particular part of the
world is observing daylight savings time or not. For events where the precise time varies by the
local time zone offset of a specific geographic location, a <a href=#valid-local-date-and-time-string>valid local date and time
string</a> combined with that geographic location is likely more useful.</p>

</dd>


Expand Down Expand Up @@ -46088,7 +46109,7 @@ interface <dfn id=htmlformelement>HTMLFormElement</dfn> : <a href=#htmlelement>H
<td class=no> &middot; <!-- Reset Button -->
<!-- <td class="no"> &middot; Button -->

</table><div class=impl>
</table><!--CLEANUP--><div class=impl>

<p>Some states of the <code title=attr-input-type><a href=#attr-input-type>type</a></code>
attribute define a <dfn id=value-sanitization-algorithm>value sanitization algorithm</dfn>.</p>
Expand Down Expand Up @@ -47303,6 +47324,13 @@ interface <dfn id=htmlformelement>HTMLFormElement</dfn> : <a href=#htmlelement>H
instead, the calendar application would have also had to explicitly
determine which time zone the user intended.</p>

<p>For events where the precise time is to vary as the user travels (e.g. "celebrate the new
year!"), and for recurring events that are to stay at the same time for a specific geographic
location even though that location may go in and out of daylight savings time (e.g. "bring the
kid to school"), the <code title=attr-input-type-datetime-local><a href="#local-date-and-time-state-(type=datetime-local)">datetime-local</a></code> type
combined with a <code><a href=#the-select-element>select</a></code> element (or other similar control) to pick the specific
geographic location to which to anchor the time would be more appropriate.</p>

</div>


Expand Down
29 changes: 29 additions & 0 deletions source
Expand Up @@ -20829,6 +20829,13 @@ this specification: the &lt;abbr>WHATWG&lt;/abbr> and the
<pre class="example">&lt;time>2011-11-12 14:54:39&lt;/time></pre>
<pre class="example">&lt;time>2011-11-12 14:54:39.929&lt;/time></pre>

<p class="note">Times with dates but without a time zone offset are useful for specifying events
that are observed at the same specific time in each time zone, throughout a day. For example,
the 2020 new year is celebrated at 2020-01-01 00:00 in each time zone, not at the same precise
moment across all time zones. For events that occur at the same time across all time zones, for
example a videoconference meeting, a <span>valid global date and time string</span> is likely
more useful.</p>

</dd>


Expand All @@ -20842,6 +20849,12 @@ this specification: the &lt;abbr>WHATWG&lt;/abbr> and the
<pre class="example">&lt;time>-0800&lt;/time></pre>
<pre class="example">&lt;time>-08:00&lt;/time></pre>

<p class="note">For times without dates (or times referring to events that recur on multiple
dates), specifying the geographic location that controls the time is usually more useful than
specifying a time zone offset, because geographic locations change time zone offsets with
daylight savings time. In some cases, geographic locations even change time zone, e.g. when the
boundaries of those time zones are redrawn, as happened with Samoa at the end of 2011.</p>

</dd>


Expand Down Expand Up @@ -20889,6 +20902,14 @@ this specification: the &lt;abbr>WHATWG&lt;/abbr> and the
<pre class="example">&lt;time>2011-11-12 06:54:39-08:00&lt;/time></pre>
<pre class="example">&lt;time>2011-11-12 06:54:39.929-08:00&lt;/time></pre>

<p class="note">Times with dates and a time zone offset are useful for specifying specific
events, or recurring virtual events where the time is not anchored to a specific geographic
location. For example, the precise time of an asteroid impact, or a particular meeting in a
series of meetings held at 1400 UTC every day, regardless of whether any particular part of the
world is observing daylight savings time or not. For events where the precise time varies by the
local time zone offset of a specific geographic location, a <span>valid local date and time
string</span> combined with that geographic location is likely more useful.</p>

</dd>


Expand Down Expand Up @@ -53618,6 +53639,7 @@ interface <dfn>HTMLFormElement</dfn> : <span>HTMLElement</span> {

</table>

<!--CLEANUP-->
<div class="impl">

<p>Some states of the <code title="attr-input-type">type</code>
Expand Down Expand Up @@ -55049,6 +55071,13 @@ interface <dfn>HTMLFormElement</dfn> : <span>HTMLElement</span> {
instead, the calendar application would have also had to explicitly
determine which time zone the user intended.</p>

<p>For events where the precise time is to vary as the user travels (e.g. "celebrate the new
year!"), and for recurring events that are to stay at the same time for a specific geographic
location even though that location may go in and out of daylight savings time (e.g. "bring the
kid to school"), the <code title="attr-input-type-datetime-local">datetime-local</code> type
combined with a <code>select</code> element (or other similar control) to pick the specific
geographic location to which to anchor the time would be more appropriate.</p>

</div>


Expand Down

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