Objective-C:http://developer.apple.com/mac/library/documentation/Cocoa/Reference/Foundation/ObjC_classic/
PHP:http://php.net/quickref.php
Java:http://java.sun.com/javase/6/docs/api/
CSS:http://www.w3schools.com/CSS/CSS_reference.asp
Python:http://docs.python.org/library/
Perl:http://perldoc.perl.org/index-modules-A.html
Ruby:http://ruby-doc.org/stdlib/
HTML:http://www.w3schools.com/tags/default.asp