PHP, MySQL, & JavaScript All-in-One For Dummies

Chapter 2

Advanced JavaScript Coding

IN THIS CHAPTER

Getting acquainted with the Document Object Model

Working with the Document Object Model

Reading data from your web page

Writing to your web page

In the previous chapter, I explain the basics of how to incorporate JavaScript code into a web page. If you read that chapter, you ran a couple of simple JavaScript programs, using the prompt() function for input and the alert() function for output. That was a great start, but the whole point of using JavaScript is to dynamically alter the data and/or appearance of web pages. This chapter explains how JavaScript interfaces with your web pages and shows you how to write JavaScript code to dynamically add, delete, or change content in your website.

Understanding the Document Object Model

In order for JavaScript to have access to the elements in your web page, it needs to know how to find them. The Document Object Model (DOM) provides a standard way of accessing objects placed within a web page. It creates a tree structure that contains every element, attribute, content text, and even ...