Hello I am using getTimezoneOffset an it returns e.g. -60

How could I set global timezone offset for javascript? I tried setTimezoneOffset('-120'); but it is not working. I would like to set it globally at start of the script so later I will be able simply call var d = new Date(); var n = d.getTimezoneOffset(); and it returns my value. Please just solution exactly for this case. Thank you!

Hello I am using getTimezoneOffset an it returns e.g. -60

How could I set global timezone offset for javascript? I tried setTimezoneOffset('-120'); but it is not working. I would like to set it globally at start of the script so later I will be able simply call var d = new Date(); var n = d.getTimezoneOffset(); and it returns my value. Please just solution exactly for this case. Thank you!

• javascript

• 1 Use UTC date methods instead of local ones, and subtract the offset when needed. – Oriol Commented Mar 29, 2014 at 0:06
• 2 Basicly Date.prototype.getTimezoneOffset = function () {return -120;}; does what you need (and exactly for your case only), but what's the point, why not use a regular variable? – Teemu Commented Mar 29, 2014 at 0:15
• 3 JavaScript doesn't really have an option built-in for specifying a timezone to use. Dates understand only 2 -- UTC/GMT and "local." And, the latter is determined by the user's system. – Jonathan Lonowski Commented Mar 29, 2014 at 0:19
• 1 Thank you guys! Especially Teemu - it works! :) Sometimes I need to have the same TimezoneOffset for all users. – peter Commented Mar 31, 2014 at 15:44

2 Answers 2

Date.prototype.getTimezoneOffset = function () {return -120;};

Using:

// TO ALL dates
Date.timezoneOffset(-240) // +4 UTC

// Override offset only for THIS date
new Date().timezoneOffset(-180) // +3 UTC

Code:

Date.prototype.timezoneOffset = new Date().getTimezoneOffset();

Date.setTimezoneOffset = function(timezoneOffset) {
  return this.prototype.timezoneOffset = timezoneOffset;
};

Date.getTimezoneOffset = function(timezoneOffset) {
  return this.prototype.timezoneOffset;
};

Date.prototype.setTimezoneOffset = function(timezoneOffset) {
  return this.timezoneOffset = timezoneOffset;
};

Date.prototype.getTimezoneOffset = function() {
  return this.timezoneOffset;
};

Date.prototype.toString = function() {
  var offsetDate, offsetTime;
  offsetTime = this.timezoneOffset * 60 * 1000;
  offsetDate = new Date(this.getTime() - offsetTime);
  return offsetDate.toUTCString();
};

['Milliseconds', 'Seconds', 'Minutes', 'Hours', 'Date', 'Month', 'FullYear', 'Year', 'Day'].forEach((function(_this) {
  return function(key) {
    Date.prototype["get" + key] = function() {
      var offsetDate, offsetTime;
      offsetTime = this.timezoneOffset * 60 * 1000;
      offsetDate = new Date(this.getTime() - offsetTime);
      return offsetDate["getUTC" + key]();
    };
    return Date.prototype["set" + key] = function(value) {
      var offsetDate, offsetTime, time;
      offsetTime = this.timezoneOffset * 60 * 1000;
      offsetDate = new Date(this.getTime() - offsetTime);
      offsetDate["setUTC" + key](value);
      time = offsetDate.getTime() + offsetTime;
      this.setTime(time);
      return time;
    };
  };
})(this));

Coffee version:

Date.prototype.timezoneOffset = new Date().getTimezoneOffset()


Date.setTimezoneOffset = (timezoneOffset)->
    return @prototype.timezoneOffset = timezoneOffset


Date.getTimezoneOffset = (timezoneOffset)->
    return @prototype.timezoneOffset


Date.prototype.setTimezoneOffset = (timezoneOffset)->
    return @timezoneOffset = timezoneOffset


Date.prototype.getTimezoneOffset = ->
    return @timezoneOffset


Date.prototype.toString = ->
    offsetTime = @timezoneOffset * 60 * 1000
    offsetDate = new Date(@getTime() - offsetTime)
    return offsetDate.toUTCString()


[
    'Milliseconds', 'Seconds', 'Minutes', 'Hours',
    'Date', 'Month', 'FullYear', 'Year', 'Day'
]
.forEach (key)=>
    Date.prototype["get#{key}"] = ->
        offsetTime = @timezoneOffset * 60 * 1000
        offsetDate = new Date(@getTime() - offsetTime)
        return offsetDate["getUTC#{key}"]()

    Date.prototype["set#{key}"] = (value)->
        offsetTime = @timezoneOffset * 60 * 1000
        offsetDate = new Date(@getTime() - offsetTime)
        offsetDate["setUTC#{key}"](value)
        time = offsetDate.getTime() + offsetTime
        @setTime(time)
        return time