Options key examples:
day:
The representation of the day.
Possible values are "numeric", "2-digit".
weekday:
The representation of the weekday.
Possible values are "narrow", "short", "long".
year:
The representation of the year.
Possible values are "numeric", "2-digit".
month:
The representation of the month.
Possible values are "numeric", "2-digit", "narrow", "short", "long".
hour:
The representation of the hour.
Possible values are "numeric", "2-digit".
minute: The representation of the minute.
Possible values are "numeric", "2-digit".
second:
The representation of the second.
Possible values are "numeric", 2-digit".
var d = new Date();
var d = new Date(milliseconds);
var d = new Date(dateString);
var d = new Date(year, month, day, hours, minutes, seconds, milliseconds);