Essential HTML, CSS, Javascript, PHP, and miscellaneous cheatsheets

Visto en Pmarca, el blog de Marc Andreseen (sí, el tipo que inventó Netscape y el concepto actual de browser tiene un blog...)

There are a ton of free cheatsheets, quick references, and downloadable resources for programming languages and related technologies online -- in this post I've tried to organize and list some of the best for web development.

I've focused on HTML, CSS, Javascript, and PHP, since those are the languages we use most commonly at Ning, but many of these sites point to resources for other languages as well.

As far as I can tell, all of the material assembled here is freely available. I've tried to avoid anything that points to pirated or illegal content. Please let me know if you see anything that isn't supposed to be free and I'll remove it from the list.

Please post suggested additions to this list as comments!

Meta-reference sites -- organized lists of references and cheatsheets:

http://www.gotapi.com/

A wonderful online API reference covering many programming languages.

http://www.digilife.be/quickreferences/quickrefs.htm

An organized list of quick references and cheatsheets.

http://techcheatsheets.com/

A great site with links to cheatsheets on lots of programming languages.

http://refcards.com/

Another great site organizing various cheatsheets.

http://whatis.techtarget.com/definition/0,289893,sid9_gci826135,00.html

A very long and thorough set of links to cheatsheets all over the web.

Other meta-reference sites:

http://mypage.bluewin.ch/yuppi/links/cheatsheets.html

http://www.petefreitag.com/item/455.cfm

http://www.smashingmagazine.com/2006/10/30/cheat-sheet-round-up-ajax-css-latex-ruby/

http://www.fuzzyfuture.com/programming/the-developer-cheat-sheet-compilation/

http://lorelle.wordpress.com/2005/10/10/html-css-php-and-more-cheat-sheets/

http://3spots.blogspot.com/2005/10/cheatsheets.html

http://webdeveloper.econsultant.com/cheat-sheets/

Key providers of cheatsheets:

http://www.visibone.com/

Visibone, the company that makes the best commercial cheatsheets for HTML, CSS, colors, etc. Site includes free resources and downloadable versions of several great cheatsheets.

http://www.ilovejackdaniels.com/cheat-sheets/

Original cheatsheets for HTML, CSS, PHP, and other technologies.

http://www.deepx.com/resources/quickref/

Original cheatsheets for CSS, XML, and related technologies.

HTML cheatsheets:

http://html-tags.info/

Free version of Visibone's HTML cheatsheet.

http://www.ucc.ie/doc/World-Wide_Web/htmlcard.html

HTML cheatsheet from Andrew Ford.

http://www.utoronto.ca/ian/books/extras/html-7nov2000.pdf

HTML cheatsheet from Ian Graham.

http://www.ilovejackdaniels.com/cheat-sheets/html-cheat-sheet/

HTML cheatsheet from ILoveJackDaniels.

http://gosquared.com/liquidicity/archives/51

HTML cheatsheet from Liquidcity.

http://www.htmlgoodies.com/beyond/reference/article.php/3472851

Maran Wilson's HTML cheatsheet.

http://www.cdburnerxp.se/htmlcheatsheet.pdf

Florian Schmitz's HTML cheatsheet.

http://www.arnspub.com/QuickRef/

An online reference to HTML organized by tag.

http://www.blooberry.com/indexdot/html/index.html

Brian Wilson's online HTML reference.

http://www.ilovejackdaniels.com/cheat-sheets/html-character-entities-cheat-sheet/

ILoveJackDaniels' HTML character entities cheatsheet.

CSS cheatsheets:

http://www.deepx.com/resources/quickref/CSS-1.0.pdf

CSS cheatsheet from DeepX.

http://www.utoronto.ca/ian/books/extras/css1-sheet-7nov2000.pdf

CSS cheatsheet from Ian Graham.

http://www.ilovejackdaniels.com/cheat-sheets/css-cheat-sheet/

CSS cheatsheet from ILoveJackDaniels. (And really, who doesn't?)

http://www.gosquared.com/liquidicity/archives/33

CSS cheatsheet from Liquidcity.

http://www.spectrum-research.com/V2/projects_css_reference.asp

CSS cheatsheet from Spectrum Research.

http://www.veign.com/downloads/guides/qrg0007.pdf

CSS cheatsheet from Veign.

http://home.tampabay.rr.com/bmerkey/cheatsheet.htm

CSS cheatsheet from Brett Merkey.

http://lesliefranke.com/files/reference/csscheatsheet.html

CSS cheatsheet from Leslie Franke.

http://www.lazycat.org/webdesign/cssref.php

CSS cheatsheet from Matt Robinson.

http://www.blooberry.com/indexdot/css/index.html

Online CSS reference from Brian Wilson.

http://meyerweb.com/eric/css/references/css1ref.html

http://meyerweb.com/eric/css/references/css2ref.html

CSS online references from Eric Meyer.

http://www.design215.com/toolbox/css_guide.php

A detailed overview of CSS from 2006 that covers features that work on most browsers.

Javascript cheatsheets:

http://wps.aw.com/wps/media/objects/2234/2287950/javascript_refererence.pdf

Addison-Wesley Javascript cheatsheet.

http://sage.math.washington.edu/home/agc/lit/javascript/javascriptcheatsheet.pdf

Javascript cheatsheet from Holmer Hemsen.

http://www.ilovejackdaniels.com/cheat-sheets/javascript-cheat-sheet/

Javascript cheatsheet from ILoveJackDaniels. (I really don't understand how he produces so many cheatsheets, drinking as much Jack as he must.)

http://www.mytechsupport.ca/tools/docs/JavaScript_Quick_Reference.pdf

Luke Terheyden's Javascript cheatsheet.

http://javascript-reference.info/

Visibone's free Javascript reference card.

http://www.visibone.com/regular-expressions/

Visibone's free Javascript regular expressions card, focused on Javascript.

http://www.quirksmode.org/js/contents.html

Extensive assortment of Javascript references on various topics.

Browser compatibility matrices:

http://www.quirksmode.org/dom/compatibility.html

http://www.quirksmode.org/css/contents.html

Comprehensive browser compatibility matrices for DOM, HTML, CSS, and event handling.

Colors:

http://www.visibone.com/colorlab/

Visibone's free interactive web color picker.

http://html-color-codes.com/

Visibone's free web color quick reference guide.

http://www.veign.com/downloads/guides/qrg0006.pdf

Veign's web color reference guide.

PHP cheatsheets:

http://www.ilovejackdaniels.com/cheat-sheets/php-cheat-sheet/

PHP cheatsheet from ILoveJackDaniels.

http://www.stevengould.org/portfolio/independent/php-refcard/PHPRefCard.pdf

PHP 4 reference card from Steven Gould.

BONUS -- Google cheatsheets:

http://www.google.com/help/cheatsheet.html

Official Google cheatsheet.

http://www.googleguide.com/advanced_operators_reference.html

Google advanced operators cheatsheet from Google Guide.

BONUS -- free downloadable programming books:

http://freecomputerbooks.com/

Outstanding site organizing links to many free programming books, tutorials, and lecture notes.

http://www.freetechbooks.com/

Another organized set of links to free programming books.

Other sites for free programming books:

http://www.techtoolblog.com/archives/195-free-online-programming-books

http://www.computer-books.us/

http://www.onlinecomputerbooks.com/