THE WINDOW OBJECT

At the core of the BOM is the window object, which represents an instance of the browser. The window object serves a dual purpose in browsers, acting as the JavaScript interface to the browser window and the ECMAScript Global object. This means that every object, variable, and function defined in a web page uses window as its Global object and has access to methods like parseInt().

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NOTE   Because window object properties are available in the global scope, many browser APIs and associated constructors use a window object property as an access point. These APIs are covered elsewhere in the book, predominantly in the JavaScript APIs chapter.

Furthermore, some of the window object's properties will drastically diverge between browsers due to differing vendor implementations. This chapter will not cover deprecated, non-standardized, or vendor-specific window properties.

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The Global Scope

Because the window object doubles as the ECMAScript Global...