Links

HTML/CSS

HTML5 Validator
CSS Validator
HTML Basics
CSS tutorial (note this uses XHTML, not HTML5)

JavaScript

JSLint
JSONLint
JavaScript Reference
jQuery documentation
Node.js 0.6.2 Documentation
The Node Beginner Book
sqlite3 library documentation

Databases

Introduction to Databases

Test 1: Relational Databases: all sections
SQL: Introduction to SQL, basic SELECT
Relational design theory: Overview, functional dependencies, Boyce-Codd normal form

Test 2: SQL: all remaining sections
Relational design theory: Multivalued dependencies
Unified modeling language: all sections
Indexes

Test 1:	Relational Databases: all sections SQL: Introduction to SQL, basic SELECT Relational design theory: Overview, functional dependencies, Boyce-Codd normal form
Test 2:	SQL: all remaining sections Relational design theory: Multivalued dependencies Unified modeling language: all sections Indexes