Javascript [Electronic resources] : The Definitive Guide (4th Edition) نسخه متنی

3.9 The Date Object

The
previous sections have described all of the fundamental data types
supported by JavaScript. Date and time values are not one of these
fundamental types, but JavaScript does provide a class of object that
represents dates and times and can be used to manipulate this type of
data. A Date object in JavaScript is created with the
new operator and the Date(
) constructor (the new operator will be
introduced in Chapter 5, and we'll learn
more about object creation in Chapter 8):

var now = new Date(  );  // Create an object holding the current date and time.
// Create a Date object representing Christmas.
// Note that months are zero-based, so December is month 11!
var xmas = new Date(2000, 11, 25);   

Methods of the Date object allow you to
get and set the various date and time values and to convert the Date
to a string, using either local time or GMT time. For example:

xmas.setFullYear(xmas.getFullYear(  ) + 1);  // Change the date to next Christmas.
var weekday = xmas.getDay(  );  // Christmas falls on a Tuesday in 2001.
document.write("Today is: " + now.toLocaleString(  ));  // Current date/time. 

The Date object also defines functions (not methods; they are not
invoked through a Date object) to convert a date specified in string
or numeric form to an internal millisecond representation that is
useful for some kinds of date arithmetic.

You can find full documentation on the Date object and its methods in
the core reference section of this book.