A cross-browser bookmarklet to examine the box-model of any DOM element on a page. Runs on Internet Explorer, Safari (and Webkit based browsers), Mozilla (including Firefox and Camino).
A DHTML shell that allows you to query the current browser window. Includes command line JavaScript execution, mouseover DOM query, CSS input, tab completion, profiler and object inspection. Can be configured to run off a bookmarklet, and works in IE, Firefox, Safari and Opera
Another Douglas Crockford video. This time Douglas talks about the Document Object Model, about how Java failed, and JavaScript evolved thanks to DHTML and DOM. He talks about how to use DOM to traversing and manipulating elements in an HTML document, walking the DOM, making elements, innerHTML, as well as Events, memory leaks. He talks about the cracks in DOM, and how we must be prepared to back off when we hit the browser limits of DOM.
Dean Edwards counters Dojo's Alex Russell's hideous hacks with two standards friendly approaches. Looking at the The DOM Content loaded problem and the sluggishness of walking a DOM Tree, Dean talks about speed improvements, including the use of XPaths.