W3C Markup Validation Service, a free service that checks Web documents in formats like HTML and XHTML for conformance to W3C Recommendations and other standards.
“For people who make websites” A List Apart Magazine explores the design, development, and meaning of web content, with a special focus on techniques and benefits of designing with web standards.
a collection of ActionScript 3 classes for building a wide variety of interactive visualizations. For example, flare can be used to build basic charts, complex animations, network diagrams, treemaps, and more.
an online accessibility testing tool designed to visually convert a full-color web page into a grayscale rendition for the purpose of visually testing the page’s perceived contrast.
intended as an entrypoint for anyone interested in the development roguelike games. If you are unfamiliar with the roguelike game genre a good definition is (modified definition taken from Balrog and originally from ADOM)
CSS allows you to create attractive navigation that, in reality, is no more than text -- text that can be marked up in such a way as to ensure that it's both accessible and understandable, By Rachel Andrew
A structured library of open-source code for PHP users - A system for code distribution and package maintenance - A standard style for code written in PHP
The first edition of this site was the outgrowth of a previous book project, Practical Relational Database Design, by Wayne Dick and Tom Jewett. The move online featured condensed discussions, an integrated view of database concepts and skills
by Jason - Color theory, "Four primary colors? Yes, why not? It’s the closest thing to the actual physiology without getting complex." (some pertinent info here http://news.ycombinator.com/item?id=2166494)