You will learn much more about how to display dates, later in this tutorial.
Date objects are created with the
new Date() constructor.
There are 4 ways to create a new date object:
new Date() creates a new date object with the current date and time:
Date objects are static. The computer time is ticking, but date objects are not.
new Date(year, month, ...) creates a new date object with a specified date and time.
7 numbers specify year, month, day, hour, minute, second, and millisecond (in that order):
January is 0. December is 11.
6 numbers specify year, month, day, hour, minute, second:
5 numbers specify year, month, day, hour, and minute:
4 numbers specify year, month, day, and hour:
3 numbers specify year, month, and day:
2 numbers specify year and month:
You cannot omit month. If you supply only one parameter it will be treated as milliseconds.
One and two digit years will be interpreted as 19xx:
new Date(dateString) creates a new date object from a date string:
Date strings are described in the next chapter.
Zero time is January 01, 1970 00:00:00 UTC.
Now the time is: milliseconds past January 01, 1970
new Date(milliseconds) creates a new date object as zero time plus milliseconds:
01 January 1970 plus 100 000 000 000 milliseconds is approximately 03 March 1973:
January 01 1970 minus 100 000 000 000 milliseconds is approximately October 31 1966:
One day (24 hours) is 86 400 000 milliseconds.
When a Date object is created, a number of methods allow you to operate on it.
Date methods allow you to get and set the year, month, day, hour, minute, second, and millisecond of date objects, using either local time or UTC (universal, or GMT) time.
Date methods and time zones are covered in the next chapters.
When you display a date object in HTML, it is automatically converted to a string, with the
toUTCString() method converts a date to a UTC string (a date display standard).
toDateString() method converts a date to a more readable format: