get client time zone from browser

Question

Is there a reliable way to get a timezone from client browser? I saw the following links but I want a more robust solution.

Auto detect a time zone with JavaScript

Timezone detection in JavaScript

Answer 1

I used an approach similar to the one taken by Josh Fraser, which determines the browser time offset from UTC and whether it recognizes DST or not (but somewhat simplified from his code):

var ClientTZ = {
    UTCoffset:  0,          // Browser time offset from UTC in minutes
    UTCoffsetT: '+0000S',   // Browser time offset from UTC in '±hhmmD' form
    hasDST:     false,      // Browser time observes DST

    // Determine browser's timezone and DST
    getBrowserTZ: function () {
        var self = ClientTZ;

        // Determine UTC time offset
        var now = new Date();
        var date1 = new Date(now.getFullYear(), 1-1, 1, 0, 0, 0, 0);    // Jan
        var diff1 = -date1.getTimezoneOffset();
        self.UTCoffset = diff1;

        // Determine DST use
        var date2 = new Date(now.getFullYear(), 6-1, 1, 0, 0, 0, 0);    // Jun
        var diff2 = -date2.getTimezoneOffset();
        if (diff1 != diff2) {
            self.hasDST = true;
            if (diff1 - diff2 >= 0)
                self.UTCoffset = diff2;     // East of GMT
        }

        // Convert UTC offset to ±hhmmD form
        diff2 = (diff1 < 0 ? -diff1 : diff1) / 60;
        var hr = Math.floor(diff2);
        var min = diff2 - hr;
        diff2 = hr * 100 + min * 60;
        self.UTCoffsetT = (diff1 < 0 ? '-' : '+') + (hr < 10 ? '0' : '') + diff2.toString() + (self.hasDST ? 'D' : 'S');

        return self.UTCoffset;
    }
};

// Onload
ClientTZ.getBrowserTZ();

Upon loading, the ClientTZ.getBrowserTZ() function is executed, which sets:

• ClientTZ.UTCoffset to the browser time offset from UTC in minutes (e.g., CST is −360 minutes, which is −6.0 hours from UTC);
• ClientTZ.UTCoffsetT to the offset in the form '±hhmmD' (e.g., '-0600D'), where the suffix is D for DST and S for standard (non-DST);
• ClientTZ.hasDST (to true or false).

The ClientTZ.UTCoffset is provided in minutes instead of hours, because some timezones have fractional hourly offsets (e.g., +0415).

The intent behind ClientTZ.UTCoffsetT is to use it as a key into a table of timezones (not provided here), such as for a drop-down <select> list.

Answer 2

Half a decade later we have a built-in way for it! For modern browsers I would use:

Intl.DateTimeFormat().resolvedOptions().timeZone

It may not work for the browser you need to support, if that is the case I would fall back to one of the libraries presented on the previous answers.

Does not work on firefox (51 and below) and IE https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DateTimeFormat/resolvedOptions#Browser_compatibility

Answer 3

you could use moment-timezone to guess the timezone:

> moment.tz.guess()
"America/Asuncion"

Answer 4

Often when people are looking for "timezones", what will suffice is just "UTC offset". e.g., their server is in UTC+5 and they want to know that their client is running in UTC-8.

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In plain old javascript (new Date()).getTimezoneOffset()/60 will return the current number of hours offset from UTC.

It's worth noting a possible "gotcha" in the sign of the getTimezoneOffset() return value (from MDN docs):

The 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, for time zone UTC+10:00 (Australian Eastern Standard Time, Vladivostok Time, Chamorro Standard Time), -600 will be returned.

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However, I recommend you use the moment.js for time/date related Javascript code. In which case you can get an ISO 8601 formatted UTC offset by running:

> moment().format("Z")
"-08:00"

(It probably bears mentioning that the client can easily falsify this information.)

Answer 5

Here is a jsfiddle

It provides the abbreviation of the current user timezone.

Here is the code sample

var tz = jstz.determine();
console.log(tz.name());
console.log(moment.tz.zone(tz.name()).abbr(new Date().getTime()));

Answer 6

Look at this repository pageloom it is helpful

download jstz.min.js and add a function to your html page

<script language="javascript">
    function getTimezoneName() {
        timezone = jstz.determine()
        return timezone.name();
    }
</script>

and call this function from your display tag