Using an offset to calculate Timezone is a wrong approach, and you will always encounter problems. Time zones and daylight saving rules may change on several occasions during a year, and It's difficult to keep up with changes.
To get the system's IANA timezone in JavaScript, you should use
console.log(Intl.DateTimeFormat().resolvedOptions().timeZone)As of April 2023, this works in 95.42% of the browsers used globally.
Old compatibility information
ecma-402/1.0 says that timeZone may be undefined if not provided to constructor. However, future draft (3.0) fixed that issue by changing to system default timezone.
In this version of the ECMAScript Internationalization API, the
timeZoneproperty will remain undefined if notimeZoneproperty was provided in the options object provided to theIntl.DateTimeFormatconstructor. However, applications should not rely on this, as future versions may return a String value identifying the host environment’s current time zone instead.
in ecma-402/3.0 which is still in a draft it changed to
Answer from PD81 on Stack OverflowIn this version of the ECMAScript 2015 Internationalization API, the
timeZoneproperty will be the name of the default time zone if notimeZoneproperty was provided in the options object provided to theIntl.DateTimeFormatconstructor. The previous version left thetimeZoneproperty undefined in this case.
Using an offset to calculate Timezone is a wrong approach, and you will always encounter problems. Time zones and daylight saving rules may change on several occasions during a year, and It's difficult to keep up with changes.
To get the system's IANA timezone in JavaScript, you should use
console.log(Intl.DateTimeFormat().resolvedOptions().timeZone)As of April 2023, this works in 95.42% of the browsers used globally.
Old compatibility information
ecma-402/1.0 says that timeZone may be undefined if not provided to constructor. However, future draft (3.0) fixed that issue by changing to system default timezone.
In this version of the ECMAScript Internationalization API, the
timeZoneproperty will remain undefined if notimeZoneproperty was provided in the options object provided to theIntl.DateTimeFormatconstructor. However, applications should not rely on this, as future versions may return a String value identifying the host environment’s current time zone instead.
in ecma-402/3.0 which is still in a draft it changed to
In this version of the ECMAScript 2015 Internationalization API, the
timeZoneproperty will be the name of the default time zone if notimeZoneproperty was provided in the options object provided to theIntl.DateTimeFormatconstructor. The previous version left thetimeZoneproperty undefined in this case.
Using getTimezoneOffset()
You can get the time zone offset in minutes like this:
var offset = new Date().getTimezoneOffset();
console.log(offset);
// if offset equals -60 then the time zone offset is UTC+01The time-zone offset is the difference, in minutes, between UTC and local time. Note that this means that the offset is positive if the local timezone is behind UTC and negative if it is ahead. For example, if your time zone is UTC+10 (Australian Eastern Standard Time), -600 will be returned. Daylight savings time prevents this value from being a constant even for a given locale
- Mozilla Date Object reference
Note that not all timezones are offset by whole hours: for example, Newfoundland is UTC minus 3h 30m (leaving Daylight Saving Time out of the equation).
Please also note that this only gives you the time zone offset (eg: UTC+01), it does not give you the time zone (eg: Europe/London).
How to get the timezone from the browser (client side) | OutSystems
How to get only the timeZone name in JavaScript?
JavaScript - how to get current time but in different time zone(s)
[AskJS] How to get the date and time base on the users timezone?
Videos
I already tried the codes below, but they don't work because they include Date and\or Time. I need to get only the timezone name. (OBS: timezone name, not IANA Time Zone)
Is it possible to force toLocaleString() to show timeZoneName "short" and "long" at same time?
Example: 5/2/2021, 02:34:28 GMT+12:45 Chatham Standard Time
Get_TimeZone_Name(Functions) for Modern Browsers (2017-2018) and for IE11!
<!DOCTYPE html>
<div id="Output"></div>
<script>
Date_Object = new Date();
document.getElementById("Output").innerText =
Date_Object.toLocaleString([], {timeZoneName:"short"}) + "\n" +
Date_Object.toLocaleDateString([], {timeZoneName:"short"}) + "\n" +
Date_Object.toLocaleTimeString([], {timeZoneName:"short"}) + "\n" +
"\n" +
Date_Object.toLocaleString([], {timeZoneName:"long"}) + "\n" +
Date_Object.toLocaleDateString([], {timeZoneName:"long"}) + "\n" +
Date_Object.toLocaleTimeString([], {timeZoneName:"long"}) + "\n" +
"\n" +
Date_Object.toLocaleString("en-US", {timeZoneName:"long"}) + "\n" +
Date_Object.toLocaleDateString("en-US", {timeZoneName:"long"}) + "\n" +
Date_Object.toLocaleTimeString("en-US", {timeZoneName:"long"}) + "\n" +
"\n" +
Date_Object.toLocaleString("pt-BR", {timeZoneName:"long"}) + "\n" +
Date_Object.toLocaleDateString("pt-BR", {timeZoneName:"long"}) + "\n" +
Date_Object.toLocaleTimeString("pt-BR", {timeZoneName:"long"}) + "\n" +
"\n" +
Date_Object.toLocaleString("ja-JP", {timeZoneName:"long"}) + "\n" +
Date_Object.toLocaleDateString("ja-JP", {timeZoneName:"long"}) + "\n" +
Date_Object.toLocaleTimeString("ja-JP", {timeZoneName:"long"}) + "\n" +
"\n" +
Date_Object.toLocaleString("ar-SA", {timeZoneName:"long"}) + "\n" +
Date_Object.toLocaleDateString("ar-SA", {timeZoneName:"long"}) + "\n" +
Date_Object.toLocaleTimeString("ar-SA", {timeZoneName:"long"}) + "\n" +
"";
</script>