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new Date().getTimezoneOffset() returns wrong time zone offset against Firefox ESR 52

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I tried to use "new Date().getTimezoneOffset()" in a javascript to return the timezone offset between the time zone on my PC and UTC time.

The time zone on my PC is UTC+8,

Javascript as below, referring to https://stackoverflow.com/questions/1091372/getting-the-clients-timezone-in-javascript

var offset = new Date().getTimezoneOffset(); console.log(offset);

It returns -60 mins. This is wrong.

Could you please advise the cause and resolution if there is?

Regards,

Sunny

I tried to use "new Date().getTimezoneOffset()" in a javascript to return the timezone offset between the time zone on my PC and UTC time. The time zone on my PC is UTC+8, Javascript as below, referring to https://stackoverflow.com/questions/1091372/getting-the-clients-timezone-in-javascript var offset = new Date().getTimezoneOffset(); console.log(offset); It returns -60 mins. This is wrong. Could you please advise the cause and resolution if there is? Regards, Sunny

All Replies (9)

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Additional info. I've tried: reinstall and ESR 45.x and change time zone several times. getTimezoneOffset() always returns -60mins.

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What does this code give?

  • new Date().toString();
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I'm in Pacific Time. Firefox 54 returns 420, which I believe means 7 hours. Since we are at -7 hours (year-round offset of -8 hours adjusted for DST), I'm not sure why 420 is a positive number.

Is your Firefox "sandboxed" in any way, such that it may not be directly reading the time from Windows 7?

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Thanks for the reply.

new. Date().toString() returns a result indicates the wrong time zone GMT+1, as below, "Thu Aug 03 2017 02:39:03 GMT+0100"

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Thanks and please fine below answer.

jscher2000 said

I'm in Pacific Time. Firefox 54 returns 420, which I believe means 7 hours. Since we are at -7 hours (year-round offset of -8 hours adjusted for DST), I'm not sure why 420 is a positive number. =>what is the time zone setting on your PC? UTC-7? Is your Firefox "sandboxed" in any way, such that it may not be directly reading the time from Windows 7? I reinstalled Firefox ESR many times and the issue persists, i did not change the browser settings. How can i know if the firefox is sandboxed or not?
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Please note that the browser in question is Firefox ESR.

Firefox non ESR has no such issue.

If you install the latest Firefox, you can easily reproduce the issue i believe.

Thanks.

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Sunny12345 said

Thanks and please fine below answer. jscher2000 said
I'm in Pacific Time. Firefox 54 returns 420, which I believe means 7 hours. Since we are at -7 hours (year-round offset of -8 hours adjusted for DST), I'm not sure why 420 is a positive number.

=>what is the time zone setting on your PC? UTC-7?

Time Zone is -8, with automatic adjustment for Daylight Savings Time. (Screenshot attached.)

Is your Firefox "sandboxed" in any way, such that it may not be directly reading the time from Windows 7?

I reinstalled Firefox ESR many times and the issue persists, i did not change the browser settings.

How can i know if the firefox is sandboxed or not?

I don't use ESR, sorry. Firefox could be sandboxed by security software or by a virtual machine program (e.g., VirtualBox). Probably you would notice other symptoms such as limitations on Firefox's ability to work with the hard drive or interact with other programs.

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This looks like UK time.

What Firefox locale do you have (about:config -> general.useragent.locale)?

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Thank you! the locale is set to locale. please refer to the attachment.