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

myArray[1] = 5;
myArray[2] = "Thomas";
myArray[3] = true;
As briefly mentioned, arrays are actually objects and have a variety of properties and methods
that can be used to manipulate them. These features will be discussed at length in Chapter 7.
However, let‘s first take at least a brief look at objects in JavaScript.
Objects
Objects can hold any type of data and are the primary mechanism by which useful tasks are
carried out. The browser provides a large number of objects for you to use. For example, you
can interact with the user through the Window object or modify the contents of a Web page
with the Document object.
Data contained in an object are said to be properties of the object. Properties are accessed with
the ―dot‖ operator, which is simply a period followed by the property name. The syntax is
objectname.propertyname
For example, you would access the lastModified property of the Document object as
document.lastModified.
Functions contained in an object are said to be methods of the object. Methods are also
accessed with the dot operator:
objectname.methodname()
In fact, we have already used methods in our previous examples. The write() method of the
Document object was used to output text to the screen:
document.write("Hello JavaScript world!");
You‘ll notice that when using objects, the length of the identifier required to access a particular
property can get quite long. For example, writing document.write might become tiresome, as
would accessing even more deeply nested sub-objects. By using the keyword with, we can
avoid referencing the full path to an object‘s property or method:
with (document)
{
}
write("this is easier ");
write("than writing out ");
write("the whole path");
Besides using built-in objects such as Document or Window, you can create your own objects
using the keyword new. The use of new was briefly demonstrated with the array examples in
the previous section. You can also destroy a property or element in an array using the keyword
delete. For example, here we define an array element and then quickly destroy it.
var myArray = new Array(4);