DHTML is the merging of HTML and JavaScript.
With DHTML we can alter the HTML page while it is
being displayed, and provide animated content to the viewer.

Read the introduction to DHTML at:
http://www.webdevelopersjournal.com/articles/dhtml2/dhtml2.html

Examples
http://www.w3schools.com/dhtml/dhtml_examples.asp
follow these examples, try it out...

Re-Create the Moveable Table
http://www.wdvl.com/Authoring/DHTML/Intro/dynamic.html

http://www.wdvl.com/Authoring/DHTML/CB/Objects/test.htm

link to your version of it from your index page

...then move on to Assignment 5
http://128.205.122.10/%7Etrebor/dms419/jessica/dhtml_layers.html