Introduction to the TreeWalker object of DOM

The TreeWalker object is a powerful DOM2 object that lets you easily filter through and create custom collections out of nodes in the document. Ok, this is sounding geeky already, but for geeky jobs requiring parsing the document tree, it doesn't hurt at all to get familiar with this object. While scripting you may have come across the need to retrieve all elements in a webpage with a specific CSS classname, or for a XML document, elements that carry a particular attribute value. The TreeWalker object makes light work of accomplishing such tasks. In this tutorial, I'll provide a introductory look at the TreeWalker object of DOM2, which is a DOM2 method supported in Firefox/Opera8+ though not IE6 or IE7 (as of beta3).



Before I continue, note that there is a cousin to the TreeWalker object called NodeIterator, which I'll cover in a future tutorial.