Skip to Main Content
Learning PHP, MySQL, and JavaScript
book

Learning PHP, MySQL, and JavaScript

by Robin Nixon
July 2009
Beginner content levelBeginner
526 pages
14h 24m
English
O'Reilly Media, Inc.
Content preview from Learning PHP, MySQL, and JavaScript

JavaScript Arrays

Array handling in JavaScript is very similar to PHP, although the syntax is a little different. Nevertheless, given all you have already learned about arrays, this section should be relatively straightforward for you.

Numeric Arrays

To create a new array, use the following syntax:

arrayname = new Array()

Or you can use the shorthand form, as follows:

arrayname = []

Assigning element values

In PHP, you could add a new element to an array by simply assigning it without specifying the element offset, like this:

$arrayname[] = "Element 1";
$arrayname[] = "Element 2";

But in JavaScript you use the push method to achieve the same thing, like this:

arrayname.push("Element 1")
arrayname.push("Element 2")

This allows you to keep adding items to an array without having to keep track of the number of items. When you need to know how many elements are in an array, you can use the length property, like this:

document.write(arrayname.length)

Alternatively, if you wish to keep track of the element locations yourself and place them in specific locations, you can use syntax such as this:

arrayname[0] = "Element 1"
arrayname[1] = "Element 2"

Example 16-8 shows a simple script that creates an array, loads it with some values, and then displays them.

Example 16-8. Creating, building, and printing an array
<script> numbers = [] numbers.push("One") numbers.push("Two") numbers.push("Three") for (j = 0 ; j < numbers.length ; ++j) document.write("Element " + j + " = " + numbers[j] + "<br />") </script> ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Start your free trial

You might also like

Web Database Applications with PHP and MySQL, 2nd Edition

Web Database Applications with PHP and MySQL, 2nd Edition

Hugh E. Williams, David Lane
Learning PHP

Learning PHP

David Sklar

Publisher Resources

ISBN: 9780596803605Supplemental ContentErrata Page