How can I get the timezone name in JavaScript?

Question

I know how to get the timezone offset, but what I need is the ability to detect something like "America/New York." Is that even possible from JavaScript or is that something I am going to have to guestimate based on the offset?

Answer 1

Most upvoted answer is probably the best way to get the timezone, however, Intl.DateTimeFormat().resolvedOptions().timeZone returns IANA timezone name by definition, which is in English.

If you want the timezone's name in current user's language, you can parse it from Date's string representation like so:

function getTimezoneName() {
  const today = new Date();
  const short = today.toLocaleDateString(undefined);
  const full = today.toLocaleDateString(undefined, { timeZoneName: 'long' });

  // Trying to remove date from the string in a locale-agnostic way
  const shortIndex = full.indexOf(short);
  if (shortIndex >= 0) {
    const trimmed = full.substring(0, shortIndex) + full.substring(shortIndex + short.length);
    
    // by this time `trimmed` should be the timezone's name with some punctuation -
    // trim it from both sides
    return trimmed.replace(/^[\s,.\-:;]+|[\s,.\-:;]+$/g, '');

  } else {
    // in some magic case when short representation of date is not present in the long one, just return the long one as a fallback, since it should contain the timezone's name
    return full;
  }
}

console.log(getTimezoneName());

Tested in Chrome and Firefox.

Ofcourse, this will not work as intended in some of the environments. For example, node.js returns a GMT offset (e.g. GMT+07:00) instead of a name. But I think it's still readable as a fallback.

P.S. Won't work in IE11, just as the Intl... solution.