date.js

(function(global) {
  global.DateTime = DateTime = {};
  DateTime.instance = (function() {
    return {
        getTime: function(date, offset, format) {
          var date = new Date(date.getTime() + offset * 1000);
          return date.getUTCHours() + ":" + date.getUTCMinutes();
        }
    };
  })();
})(window);