Denilson Figueiredo de Sá

Web (HTML/CSS/JavaScript/DOM)

HTML 4.01 Specification
Official W3C HTML 4.1 specs.
CSS 2.1 Specification
Official W3C CSS 2.1 specs.
www.HowToCreate.co.uk
Excellent site with lots of good tutorials about HTML, CSS, JavaScript and DOM. The author always try to make things cross-browser and standard compliant.
BrainJar.com
Nice site with nice DOM tutorials and already made scripts. However, some scripts are not really cross-browser. DOM tutorials are nice to beginners, though.
Ampersands, PHP Sessions and Valid HTML
Why using PHP sessions causes invalid HTML and XHTML to be generated, and how to fix it.
dean.edwards.name/IE7/
IE7 is a JavaScript library to make IE behave like a standards-compliant browser. It fixes many CSS issues and makes transparent PNG work correctly under IE5 and IE6.
Sending XHTML as text/html Considered Harmful
An excellent text that says you must not use XHTML if you do not understand it.
Client-Side JavaScript 1.3 Reference
Old documentation of JavaScript 1.3, previously available at Netscape site.
Document Object Model (DOM) Technical Reports
W3C DOM specification.
Supporting IE with conditional comments
Excellent article.
Is HTML5 ready yet?