HTML

• HTML/XTML in one page
• HTML5: The Evolution of Web Standards by James Sugrue
• (X)HTML Elements and Attributes
• Doctype Declarations (DTDs)
• XHTML Character Entity Reference
• GoSquared HTML Help Sheet

CSS

• CSS in one page
• CSS Properties and Values
• All CSS Properties Listed Alphabetically
• CSS Shorthand Guide
• GoSquared CSS Help Sheet

PHP

• PHP Basics Quick Reference Sheet
• PHP Cheat Sheet
• PHP Security Cheat Sheet
• PHP Variable and Array Tests
• GoSquared PHP Help Sheet

JavaScript

• JavaScript in one page
• JavaScript Cheat Sheet
• Addison-Wesley’s JavaScript Reference Card

XML & Unicode

• XML in one page
• XML 1.0 Syntax Quick Reference by Mulberry Technologies

• The Unicode Character Code
• HTML Characters, Numeric Codes, 0-65535 by Bob Stein