The BOM is a collection of objects that give you access to the browser and the computer screen. These objects are accessible through the global object window
.
As you already know, in JavaScript, there's a global object provided by the host environment. In the browser environment, this global object is accessible using window
. All global variables are also accessible as properties of the window
object. For example, take a look at the following code:
> window.somevar = 1; 1 > somevar; 1
Additionally, all the core JavaScript functions, discussed in Chapter 2, Primitive Data Types, Arrays, Loops, and Conditions, are methods of the global object. Consider the following piece of code:
> parseInt('123a456'); 123 > window.parseInt('123a456'); 123
In addition to being a reference to the global object, the window
object also serves a second purpose-providing...