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Browser Object Model

The Browser Object Model

You can’t really talk about JavaScript in the browser without talking about the Browser Object Model

(BOM), which provides objects that interact with the browser window independent of the content.

The BOM is made up of a series of objects that are related to one another. Figure 5-3 shows the basic

BOM hierarchy.

Figure 5-3

As you can see, the

window

object is the center of the BOM universe, with all objects and collections

somehow connecting back to it. I begin the discussion of the BOM with this object.

The window object

The

window

object represents an entire browser window, but not necessarily the content that the win-

dow contains. Rather,

window

can be used to move, resize, and otherwise affect the browser that it

represents.

If a page uses framesets, each frame is represented by its own

window

object and stored in the

frames

collection. Within the

frames

collection, the window objects are indexed both by number (starting at

0, going first left-to-right, then row-by-row) and by the name of the frame. Consider the following

example:

<html>

<head>

<title>Frameset Example</title>

window

document

location

histor y

location

navigator

screen

Array

frames

anchors

forms

images

links

Object

KEY

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Chapter 5

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