Other areas of the site are equally valuable. My favorite is the cross platform positioning library. This allows you to create cross platform DHTML using these calls.
The CSS online section is the most complete intro to Cascading Style Sheets that I've seen. It talks about them in general and goes into the syntax and how to use it. CSS is the foundation of the Document Object Model for IE 4.0. Once you've got your objects positioned then its time for the fun stuff. Moving them around the screen.
The Resource section is also very good. Links to many of the better DHTML pages on the web. Unfortunately there are also links to some of the lousy sites on the web. Yours truly DHTML Demos is included on the page coming in at a surprising #2 (we try harder) out of 17.
Jeff