By default, JavaScript will use the browser's time zone and display a date as a full text string:
Sat Jun 12 2021 13:39:02 GMT+0530 (India Standard Time)
Creating Date Objects
Date objects are created with the new Date() constructor.
There are 4 ways to create a new date object:
new Date(year, month, day, hours, minutes, seconds, milliseconds)
new Date(milliseconds)
new Date(date string)
new Date()
new Date() creates a new date object with the current date and time:
Example
new Date(year, month, ...)
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):
Example
Note: JavaScript counts months from 0 to 11.
January is 0. December is 11.
6 numbers specify year, month, day, hour, minute, second:
Example
5 numbers specify year, month, day, hour, and minute:
Example
4 numbers specify year, month, day, and hour:
Example
3 numbers specify year, month, and day:
Example
2 numbers specify year and month:
Example
You cannot omit month. If you supply only one parameter it will be treated as milliseconds.
Example
Previous Century
One and two digit years will be interpreted as 19xx:
Example
Example
new Date(dateString)
new Date(dateString) creates a new date object from a date string:
Example
JavaScript Stores Dates as Milliseconds
JavaScript stores dates as number of milliseconds since January 01, 1970, 00:00:00 UTC (Universal Time Coordinated).
Zero time is January 01, 1970 00:00:00 UTC.
Now the time is: 1623485342335 milliseconds past January 01, 1970
new Date(milliseconds)
new Date(milliseconds) creates a new date object as zero time plus milliseconds:
Example
01 January 1970 plus 100 000 000 000 milliseconds is approximately 03 March 1973:
Example
January 01 1970 minus 100 000 000 000 milliseconds is approximately October 31 1966:
Example
Example
One day (24 hours) is 86 400 000 milliseconds.
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