DOM CHANGES
The purpose of the DOM Levels 2 and 3 Core is to expand the DOM API to encompass all of the requirements of XML and to provide for better error handling and feature detection. For the most part, this means supporting the concept of XML namespaces. DOM Level 2 Core doesn't introduce any new types; it simply augments the types defined in DOM Level 1 to include new methods and properties. DOM Level 3 Core further augments the existing types and introduces several new ones.
Similarly, DOM Views and HTML augment DOM interfaces, providing new properties and methods. These two modules are fairly small and so are grouped in with the Core to discuss changes to fundamental JavaScript objects.
XML Namespaces
XML namespaces allow elements from different XML-based languages to be mixed together...