Tutorials – php, js, css, photo

I am thinking about starting new site:

http://tutorials.robi-bobi.net/

I will post there some tutorials that can be usefull. I already have two in mind:
- tutorial about showing and hiding part of html pages with javascript and css (by using div and tr tags)
- tutorial about XmlHttpRequests (hm, I might even write some library and post it to : http://projects.robi-bobi.net/)