Really nice little tutorial on accessing/manipulating the DOM via JavaScript.
#dom
jQuery Taconite Plugin
“The jQuery Taconite Plugin allows you to easily make multiple DOM updates using the results of a single AJAX call. It processes an XML command document that contain instructions for updating the DOM.”
phpquery
“phpQuery is a server-side, chainable, CSS3 selector driven Document Object Model (DOM) API based on jQuery JavaScript Library.”