Arrays and objects are both a collection of data values (string, number, boolean, or object). Consider the following code that creates two objects. And remember, an empty array and empty object are both objects. That is why we refer to them as "array object" and "object object".

var myArrayObject = ["a", "b", "c"] 
// collection of strings created using an array literal, which creates an array object

var myObjectObject = {a:"first letter of alphabet", b:"second letter of alphabet", "c":"third letter of alphabet"}
// collection of strings created using an object literal, which creates an object object

Array objects treat the collection as ordered values. Meaning that each value (often called an element) in an array collection is giving a numeric index starting with 0. So the following code will reference the value of the third element in the myArrayObject array.

alert(myArrayObject[2]); //alerts "c"

Object objects treat the collection as unordered named values. Meaning that each value (often called a property) in an object is given a name. The name can be an identifier or string. So the following code will reference the value of the property named c, in the myObjectObject object. It should be noted that c is a string.

alert(myObjectObject.c); //alerts "third letter of alphabet"

Now if your javascript kung fu is top notch then you also know that you could obtain the property value of c using a string instead of an identifier. Like so:

alert(myObjectObject["c"]); //alerts "third letter of alphabet"

Accessing the value of c like we just did is often called an associate array. Which seems silly. Because an associate array is really an object object and not an array object. But then again an array is really just a special kind of object object.