JavaScript 2.0-The Complete Reference, Second ... - freecodingtutorial

Table 7-1: Arguments to the Date() Constructor
Argument Description Example
"month dd, yyyy
hh:mm:ss"
Creates object with the date
represented by the specified month,
day (dd ),
year ( yyyy ), hour (hh), minute
(mm),
and second (ss). Any omitted
values
are set to zero.
Milliseconds Creates object with date
represented as the integer number
of milliseconds after the epoch.
yyyy, mm, dd Creates object with the date
specified by the integer values year
(yyyy),
month (mm), and day (dd).
yyyy, mm, dd, hh, mm,
ss
yyyy, mm, dd, hh, mm,
ss, ms
Creates object with the date
specified by the integer values for
the year, month, day, hours,
minutes, and seconds.
Creates object with the date
specified by the integer values for
the year, month, day, hours,
seconds, and milliseconds.
var birthDay = new
Date("March 24,
1970");
var someDate = new
Date(795600003020);
var birthDay = new
Date(1970, 2, 24);
var birthDay = new
Date(1970, 2, 24,
15, 0, 0);
var birthDay = new
Date(1970, 2, 24,
15, 0, 250);
Table 7-1 warrants some commentary. The string version of the constructor argument can be
any date string that can be parsed by the Date.parse() method. In the syntax of the last two
formats, the arguments beyond the year, month, and day are optional. If they are omitted, they
are set to zero. The final syntax that includes milliseconds is available only in JavaScript 1.3+.
Note Because of the ambiguity that arises from representing the year with two digits, you
should always use four digits when specifying the year. This can be done using the
getFullYear() method discussed later in this section.
It is important to note that Date objects you create are static. They do not contain a ticking
clock. If you need to use a timer of some sort, the setInterval() and setTimeout() methods of
the Window object are much more appropriate. These other methods are discussed both in
Appendix B and in later application-oriented chapters.
Date objects are created to be picked apart and manipulated and to assist in formatting dates
according to your specific application. You can even calculate the difference between two dates
directly:
var firstDate = new Date(1995, 0, 6);var secondDate = new Date(1999, 11, 2);var difference =
secondDate - firstDate;alert(difference);
The result indicates the approximate number of milliseconds elapsed between January 6, 1995,
and December 2, 1999: