A few weeks ago, we have provided you the useful resources help you to learn HTML5. Following that post, many our readers showed interest in having cheat sheets to help you write code easily. Cheat Sheet is concise set of notes commonly used for quick reference. It is a very useful thing if you want to code smarter. It is not a shocking thing that the skills of many web designers today go beyond just designing, they can do some part of programming also. So whether you are an experienced programmer or just started to learn how to code, here are cheat sheets that are going to be a big help to you.
The WordPress Help Sheet
The Advanced WordPress Help Sheet
ExpressionEngine
ExpressionEngine Quick Reference Chart
PHP
PHP Cheat Sheet
MYSQL
MySQL Cheat Sheet
Ruby on Rails
Ruby on Rails Cheat Sheet
JavaScript
JavaScript Cheat Sheet
Scriptaculous Cheat Sheet
jQuery 1.3 Cheat Sheet
MooTools 1.2 Cheat Sheet
Prototype 1.6.0.2 Cheat Sheet
XHTML
(X)HTML Elements and Attributes
HTML/XHTML In One Page
CSS
CSS Cheat Sheet (V2)
CSS Cheat Sheet
ActionScript
Actionscript 2.0 Cheat Sheet Flashpaper 
ActionScript 2.0 to 3.0 Migration Cheatsheets
Papervision 3D Cheat Sheets
Other resources
The people at Dzone have some more great cheat sheets for developers and designers. Check it out: RefCardz