Question

I have simple script:

function test(time) {
    var dt = new Date( time * 1000 )
    var sec = dt.getSeconds()
    if ( sec < 10 ) sec = "0" + sec
    var min = dt.getMinutes()
    if ( min < 10 ) min = "0" + min
    var hour = dt.getHours()
    if ( hour < 10 ) hour = "0" + hour
    var time = hour + ":" + min + ":" + sec
    return time

expected resut (test(1800) ) : 30:00, but I have result: 04:30:00. Can you help me correct this script ?
My timezone GMT+04

Answer 1

The answer is very simple:

The constructor of Date object can accept an:

Integer value representing the number of milliseconds since 1 January 1970 00:00:00 UTC (Unix Epoch)

While Date.get* functions return using local timezone.

If you really need to, use Date.getUTC* instead.

function test(time) {
    var dt = new Date( time * 1000 );
    var sec = dt.getUTCSeconds();
    if ( sec < 10 ) sec = "0" + sec;
    var min = dt.getUTCMinutes();
    if ( min < 10 ) min = "0" + min;
    var hour = dt.getUTCHours();
    if ( hour < 10 ) hour = "0" + hour;
    var time = hour + ":" + min + ":" + sec;
    return time;
}