To be able to successsfully work with the DOM, first we need to understand what it is. DOM stands for Document Object Model and it is the way browsers represent the structure of your HTML (XHTML or XML) document so JS can navigate it (actually it is supposed to be language agnostic, but I’ll explain how to interact with it using JS), or modify it.
The way you can access the DOM in a typical browser is by refering to the window variable. The window variable gives you access to attributes like history, location and document. In this articule I will focus on window.document.