我的计时器中的时区javascript

I have found a code but i dont know to add timezone . i want to detect the timer from the timezone of the other country like denmark/copenhagen. thank you. this is my code.

<script type="text/javascript">
ElapsedTimeLogger = function(dateElementId, elapsedElementId, hiden, interval) {
    var container = $(elapsedElementId);
    var time = parseDate($(dateElementId).val());
    var interval = interval;
    var timer;

    function parseDate(dateString) {
        var date = new Date(dateString);
        return date.getTime();
    }

    function update() {
    var systemTime = new Date().getTime();
    elapsedTime = systemTime - time;
    container.html(prettyPrintTime(Math.floor(elapsedTime / 1000)));
$(hiden).val(prettyPrintTime(Math.floor(elapsedTime / 1000)));
}

    function prettyPrintTime(numSeconds) {
        var hours = Math.floor(numSeconds / 3600);
        var minutes = Math.floor((numSeconds - (hours * 3600)) / 60);
        var seconds = numSeconds - (hours * 3600) - (minutes * 60);

        if (hours < 10) hours = "0" + hours;
        if (minutes < 10) minutes = "0" + minutes;
        if (seconds < 10) seconds = "0" + seconds;
        var time = hours + ":" + minutes + ":" + seconds;

        return time;
    }

    this.start = function() {

        timer = setInterval(function() {update()}, interval * 1000);
    }

    this.stop = function() {
        clearTimeout(timer);
    }
}
$(document).ready(function () {

    var timeLogger = new ElapsedTimeLogger("#date", "#elapsed","#stoppedid", 1);
    timeLogger.start();

   $("#confirm").click(function() { //Stop timer upon clicking the Confirm Button 
        timeLogger.stop();

    });

});

    </script>

thank you. i dont know javascript. i know php only. i tried to put

before the code is running. i already save a time from europe/copenhagen. but when the timer is running. it says 6:00:01 abd counting.. but i want to run like this 0:00:01 and counting. and my idea the time from europe and time in my country is 6 hours. i want to run the time from europe not my country. because i save the time from europe using php. see bellow the code for save the time.

date_default_timezone_set("Europe/Copenhagen");

but wont work. i didnt found the solution

</div>

function getClientTimeZone() {
  var offset = new Date().getTimezoneOffset(),
    o = Math.abs(offset);
  return (offset < 0 ? "+" : "-") + ("00" + Math.floor(o / 60)).slice(-2) + ":" + ("00" + (o % 60)).slice(-2);
}

// Display Output
alert(getClientTimeZone());

Analyzing this code, I rewrote the needed HTML to see what the code do. It's simply creates a counter in format hh:mm:ss and shows on screen, this counter show the time passed since the date informed.

to add the user timezone to reflect in your timer, you just need to recalculate the seconds inside the prettyPrintTime(numSeconds) function before use it to get hours, minutes and seconds.

function prettyPrintTime(numSeconds) {
            var tzOffset = new Date().getTimezoneOffset();  // get the timezone in minutes
            tzOffset = tzOffset * 60;   // convert minutes to seconds
            numSeconds -= tzOffset;     // recalculate the time using timezone

            var hours = Math.floor(numSeconds / 3600);
            var minutes = Math.floor((numSeconds - (hours * 3600)) / 60);
            var seconds = numSeconds - (hours * 3600) - (minutes * 60);

            if (hours < 10) hours = "0" + hours;
            if (minutes < 10) minutes = "0" + minutes;
            if (seconds < 10) seconds = "0" + seconds;
            var time = hours + ":" + minutes + ":" + seconds;

            return time;
        }

Take a look at the working code: https://jsfiddle.net/4c6xdcpr/