[Rise]

AntonMs,

var newDate = new Date();

alert(newDate.getUTCHours() + ':' + newDate.getUTCMinutes());

newDate.setMilliseconds(2 * 60 * 60 * 1000);  // +2 часа

alert(newDate.getUTCHours() + ':' + newDate.getUTCMinutes());

newDate.setMilliseconds(-3 * 60 * 60 * 1000); // -3 часа

alert(newDate.getUTCHours() + ':' + newDate.getUTCMinutes());