What the W3C DOM Does and How
As stated above, the W3C DOM gives you the facility to manipulate the content of an HTML document once it's arrived in the user’s web browser. Unlike older versions of client-side Javascript manipulation, the W3C DOM allows you to manipulate practically every aspect of a document.
It does this by providing access to the document as if it were a tree structure. The tree is made up of nodes of three types:
Text Nodes – These correspond to text data in our document
Element Nodes – These correspond to HTML elements like <p>, <em> and <div>