const timezone = Intl.DateTimeFormat().resolvedOptions().timeZone;

console.log(timezone);

console.log(Intl.DateTimeFormat().resolvedOptions().timeZone)

var d = new Date("2020-04-13T00:00:00.000+08:00"); /* midnight in China on April 13th */

d.toLocaleString('en-US', { timeZone: 'America/New_York' });

//=> "4/12/2020, 12:00:00 PM"

// (midnight in China on April 13th is noon in New York on April 12th)

const browserTimezone = Intl.DateTimeFormat().resolvedOptions().timeZone;

console.log(browserTimezone);

// current datetime string in America/Chicago timezone

let chicago_datetime_str = new Date().toLocaleString("en-US", { timeZone: "America/Chicago" });

​

// create new Date object

let date_chicago = new Date(chicago_datetime_str);

​

Intl.DateTimeFormat().resolvedOptions().timeZone

​

getGMT() {

    let gmtFigure = new Date().getTimezoneOffset() / -60;

    let gmtSign = gmtFigure >= 0 ? '+' : '-';

    let gmtlength = this.digits_count(gmtFigure);

    let gmt = 'GMT';

    if (gmtlength == 1) {

      gmt += gmtSign + '0' + Math.abs(gmtFigure);

    } else if (gmtlength > 1) {

      gmt += gmtSign + Math.abs(gmtFigure);

    }

    return gmt;

  }

​

​

digits_count(n) {

    var count = 0;

    n = Math.abs(n);

    if (n >= 1) ++count;

    while (n / 10 >= 1) {

      n /= 10;

      ++count;

    }

    return count;

  }

function changeTimezone(date, ianatz) {

​

  // suppose the date is 12:00 UTC

  var invdate = new Date(date.toLocaleString('en-US', {

    timeZone: ianatz

  }));

​

  // then invdate will be 07:00 in Toronto

  // and the diff is 5 hours

  var diff = date.getTime() - invdate.getTime();

​

  // so 12:00 in Toronto is 17:00 UTC

  return new Date(date.getTime() - diff); // needs to substract

​

}

​

// E.g.

var here = new Date();

var there = changeTimezone(here, "America/Toronto");

​

console.log(`Here: ${here.toString()}\nToronto: ${there.toString()}`);

 Run code snippetHide results