a bible of transitioning and progressive enhancement back when nobody was certain about the direction of HTML working groups and browser support. By Mark Pilgrim
“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.
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.