JavaScript and Ajax for the Web: Visual QuickStart Guide, Seventh Edition

Properties

Objects have properties. A cat has fur, the computer has a keyboard, and the bicycle has wheels. In the JavaScript world, a window has a title, and a form can have a check box.

Changing a property of an object modifies that object, and the same property name can be a part of completely different objects. Let’s say that you have a property called empty. It’s okay to use empty wherever it applies, so you could say that both the cat’s tummy is empty and the cat’s bowl is empty.

Note that the computer’s keyboard and the bicycle’s wheels aren’t only properties; they are also objects in their own right, which can have their own properties. So objects can have sub-objects.