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

Chapter 9. Arrays

Chapter 8 documented the
JavaScript object type -- a composite data type that holds named
values. This chapter documents arrays -- a composite data type
that holds numbered values. Note that the arrays we'll discuss
in this chapter are different from the associative arrays described
in the previous chapter. Associative arrays associate values with
strings. The
arrays described in this chapter are just regular numeric arrays;
they associate values with non-negative integers.

Throughout this book, we often treat objects and arrays as distinct
data types. This is a useful and reasonable simplification; you can
treat objects and

arrays as separate types for most of your
JavaScript programming. To fully understand the behavior of objects
and arrays, however, you have to know the truth: an array is nothing
more than an object with a thin layer of extra functionality. We see
this when we use the
typeof operator: applied to an array value,
it returns the string "object". Note that the extra
functionality of arrays was introduced in JavaScript 1.1. Arrays are
not supported in JavaScript 1.0.

This chapter documents basic array syntax, array programming
techniques, and methods that operate on arrays.