This section provides an overview of DOM (Document Object Model) specifications, which is a set of API divided into multiple levels and modules (features).
DOM (Document Object Model) is a set of specifications recommended by W3C (World Wide Web Consortium)
to define an API (Application Programming Interface) valid HTML and well-formed XML [p.208] documents.
Currently, DOM has 4 levels of specifications:
DOM Level 0 - No formal specifications published: A collection of HTML document functionalities
offered by Netscape Navigator version 3.0 and Microsoft Internet Explorer version 3.0.
Examples of DOM Level 0 functionalities: document.bgColor, and document.alinkColor.
DOM Level 1 - Latest version published in October, 1998:
An API of 2 modules: Core and HTML. DOM Level 1 Core
represents the functionality used for XML documents.
DOM Level 1 HTML extends DOM Level 1 Core to represents functionality specific to HTML documents.
Examples of DOM Level 1 functionalities: document.createElement(), and document.body.bgColor.
DOM Level 2 - Published in November, 2000: An API of 14 modules:
Core, XML, HTML, Views, StyleSheets, CSS, CSS2, Events, User interface Events, Mouse Events, Mutation Events,
HTML Events, Range, and Traversal.
Examples of DOM Level 2 functionalities: document.defaultView, document.styleSheets, document.getElementById(),
and document.body.style.
DOM Level 3 - Published in April, 2004: An API of 21 modules:
Core, XML, HTML, XPath, Travesal, Range, Validation, Load and Save, Asynchronous Load,
Views, Stylesheets, CSS, CSS2, Events, HTML Events, Mutation Events, Mutation Name Events,
UI Events, Mouse Events, Text Events, and Keyboard Events.
Examples of DOM Level 3 functionalities: document.xmlVersion, document.inputEncoding, and
document.title.textContent.
