Script reverse report with GMT timezone how to do?

Question

JavaScript

Help to fasten to this script of the return report, the time zone.
It is necessary that everyone who visits the site has the same time before X hour

<strong id="timer"></strong>
    <script>
    var outTimer = document.getElementById('timer'),
       secEnd = 11.00 * 3600, // секунд до 1:00
       serDay = 24 * 3600; // секунд в сутках
     
    setInterval(function () {
       var curDate = new Date(),
           curSec = curDate.getHours() * 3600 + curDate.getMinutes() * 60 + curDate.getSeconds() * 01,
           diff = secEnd - curSec;
     
       if (diff < 0) {
           diff = serDay + diff;
       }
     
       var hours = Math.floor(diff / 3600),
           minutes = Math.floor(diff / 60) % 60,
           seconds = Math.floor(diff) % 60;
     
       if (hours < 10) hours = '0' + hours;
       if (minutes < 10) minutes = '0' + minutes;
       if (seconds < 10) seconds = '0' + seconds;
       
       outTimer.innerHTML = hours + ':' + minutes + ':' + seconds;
    }, 10);
    </script>

Answer 1

momentjs.com