DOM is an essential element in newer technologies like Java and XML, XSL(T) etc. To understand these technologies, you should have a good understanding of the Document Object Model and how you modify the DOM tree.
Links:
- Document Object Model (DOM)
- Document Object Model FAQ
- What is the Document Object Model?
- DOM Level 3
- Document Object Model Traversal
- Document Object Model Core
- Dynamically creating a DOM tree
- Replacing a Node in a DOM Tree of an XML Document with Sun Java
- 2D Web Graphics: SVG: Interaction with the DOM Tree