To set your time zone using Javascript you may use as follows.
Code with examples
let CountryDate = new Date().toLocaleString("en-US", {timeZone: "Continent/Your City"});
An example based on New York:
toLocaleString('en-US', {timeZone: 'America/New_York'});
London would be like below:
toLocaleString('en-GB', {timeZone: 'Europe/London'});
As you may notice I specified a language as well.