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/)