JavaScript® Bible, Sixth Edition

Chapter 4. Browser and Document Objects

IN THIS CHAPTER

• What client-side scripts do

• What happens when a document loads

• How the browser creates objects

• How scripts refer to objects

• What distinguishes one object from another

This chapter marks the first of nine tutorial chapters tailored to web authors who have at least basic grounding in HTML concepts. In particular, you should already be familiar with common HTML tags and their attributes, as well as the fundamentals of Cascading Style Sheets (CSS). In this chapter, you see several practical applications of JavaScript and begin to see how a JavaScript-enabled browser turns familiar HTML elements into objects that your scripts control. This tutorial teaches concepts and terminology that apply to modern browsers, with special focus on standards compatibility to equip you to work with today's and tomorrow's browsers. You should study this tutorial in conjunction with any of the following browsers: Internet Explorer 5 or later (Windows or Macintosh), any Mozilla-based browser (Firefox, Netscape 7 or later, or Camino), Apple Safari, or Opera 7 or later.

Scripts Run the Show

If you have authored web pages with HTML, you are familiar with how HTML tags influence the way content is rendered on a page when viewed in the browser. As the page loads, the browser recognizes angle-bracketed tags as formatting instructions. Instructions are read from the top of the document downward, and elements defined in the HTML document appear onscreen in the same ...