WHAT IS THE DOM?

The Document Object Model provides a scripting interface into an HTML document so that you can work with all of its elements within a hierarchical structure. As a result, you can navigate through the document structure with JavaScript to access and manipulate anything inside it.

The DOM is a standard that was originated by the W3C, the Web standards body. There are three DOM levels:

• Level 1: Level 1 contains the core functionality to be able to script the DOM for an HTML or XML document. Any modern browser provides support for the Level 1 version of the DOM.
• Level 2: Level 2 support extends DOM support to include new core functionality, event listeners, and CSS DOM. Safari and other browsers provide generally strong support for most aspects of DOM2.