[RFC|Merged] Switch to PHP timezone handling

[Oleg]

It is impossible to know what timezone a user is in from their dst offset alone.

It should also be possible to choose any timezone we support whenever timezone choice is presented.

[callumacrae]

It is impossible to know what timezone a user is in from their dst offset alone.

It should also be possible to choose any timezone we support whenever timezone choice is presented.

new Date().toString() provides more info:

"Wed Aug 24 2011 08:41:41 GMT+0100 (BST)"

It's standardised across all browsers and is easy to parse.

[teikjoon]

I've wrote a small bit of Javascript which calculates your timezone offset, and then uses this to select the "default" option (which is hardcoded to UTC +0) :

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<script type="text/javascript">
 
var d = new Date()
var gmtHours = -d.getTimezoneOffset()/60;
 
for (var i=0;i<document.getElementById("timezone").options.length;i++) {
    if (document.getElementById("timezone").options[i].value == gmtHours)
        document.getElementById("timezone").options[i].selected = true;
}
 
</script>

Which seems to work, working example here : http://www.workshop.twofishy.net/phpbb/ ... ezone.html

[Noxwizard]

It does not correctly take DST into account. So UTC-5 EST was selected instead of UTC-6 CST w/DST.

[teikjoon]

Hrmn, what about this...grep the timezone string for the word "Daylight", and if it appears, minus an hour from the offset :

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if (d.toString().indexOf("Daylight")!=-1) gmtHours--;

Have updated http://www.workshop.twofishy.net/phpbb/ ... ezone.html to reflect this change.

It does not correctly take DST into account. So UTC-5 EST was selected instead of UTC-6 CST w/DST.

[Noxwizard]

The output varies by browser, so that won't really work. Additionally, I don't know if browsers localize those strings or not.

Chrome:

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Thu Aug 25 2011 02:06:02 GMT-0500 (Central Daylight Time)

IE:

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Thu Aug 25 02:06:02 CDT 2011

[callumacrae]

The output varies by browser, so that won't really work. Additionally, I don't know if browsers localize those strings or not.

Chrome:

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Thu Aug 25 2011 02:06:02 GMT-0500 (Central Daylight Time)

IE:

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Thu Aug 25 02:06:02 CDT 2011

new Date().toString() is, according to DavidIQ, standardised across all browsers:

"Thu Aug 25 2011 19:54:00 GMT+0100 (BST)"

[Noxwizard]

I'm not sure in what version of the browsers they plan to do that in, but the two I gave are using the JavaScript you listed. That's Chrome 13 and IE 9.

[DavidIQ]

new Date().toString() is, according to DavidIQ, standardised across all browsers:

"Thu Aug 25 2011 19:54:00 GMT+0100 (BST)"

Yeah...they looked the same to me. Should have checked to begin with Might be best to go with getTimezoneOffset and try to figure it out from there as that seems pretty standard between at least FF and IE9:
http://www.davidiq.net/jsdatetest.htm

[nickvergessen]

Safari 5.1

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.toString() = Fri Aug 26 2011 00:09:29 GMT+0200 (Mitteleuropäische Sommerzeit)
.toUTCString() = Thu, 25 Aug 2011 22:09:29 GMT
.getTimezoneOffset() = -120

Opera 11.50

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.toString() = Fri Aug 26 2011 00:09:34 GMT+0200
.toUTCString() = Thu, 25 Aug 2011 22:09:34 GMT
.getTimezoneOffset() = -120