The documentation on jquery.com is in the form of a wiki, which means that the content is editable by the public. The site includes the full jQuery API, tutorials, getting started guides, a plug-in repository, and more:

http://docs.jquery.com/

On jQuery.com, the API is available in two locations—the documentation section and the paginated API browser.

The documentation section of jQuery.com includes not only jQuery methods, but also all of the jQuery selector expressions:

http://docs.jquery.com/Selectors

http://docs.jquery.com/

http://jquery.com/api

Jörn Zaeferrer has put together a convenient tree-view browser of the jQuery API with a search feature and alphabetical or category sorting:

http://jquery.bassistance.de/api-browser/

This API browser designed by Yehuda Katz is both beautiful and convenient. It also provides quick viewing of methods for a number of jQuery plug-ins:

http://www.visualjquery.com/

Sam Collet keeps a master list of jQuery documentation, including downloadable versions and cheat sheets, on his blog:

http://webdevel.blogspot.com/2007/01/jquery-documentation.html

This site has a comprehensive JavaScript reference, a guide to programming with JavaScript, links to helpful tools, and more:

http://developer.mozilla.org/en/docs/JavaScript/

While focused primarily on its own browser platform, Opera's site for web developers includes a number of useful articles on JavaScript:

http://dev.opera.com/articles/

Peter-Paul Koch's Quirksmode site is a terrific resource for understanding differences in the way browsers implement various JavaScript functions, as well as many CSS properties:

http://www.quirksmode.org/

Matt Kruse's JavaScript Toolbox offers a large assortment of homespun JavaScript libraries, as well as sound advice on JavaScript best practices and a collection of vetted JavaScript resources elsewhere on the Web:

http://www.javascripttoolbox.com/

This JavaScript compressor/obfuscator by Dean Edwards is used to compress the jQuery source code. It's available as a web-based tool or as a free download. The resulting code is very efficient in file size, at a cost of a small increase in execution time:

http://dean.edwards.name/packer/

http://dean.edwards.name/download/#packer

Created by Douglas Crockford, JSMin is a filter that removes comments and unnecessary white space from JavaScript files. It typically reduces file size by half, resulting in faster downloads:

http://www.crockford.com/javascript/jsmin.html

This tool prettifies JavaScript that has been compressed, restoring line breaks and indentation where possible. It provides a number of options for tailoring the results:

http://www.prettyprinter.de/

The World Wide Web Consortium (W3C) sets the standard for (X)HTML, and the HTML home page is a great launching point for its specifications and guidelines:

http://www.w3.org/MarkUp/

The W3C's CSS home page provides links to tutorials, specifications, test suites, and other resources:

http://www.w3.org/Style/CSS/

Dave Shea provides this helpful CSS cribsheet in an attempt to make the design process easier, and provide a quick reference to check when you run into trouble:

http://mezzoblue.com/css/cribsheet/

This site includes a catalog of CSS browser bugs along with explanations of how to overcome them:

http://www.positioniseverything.net/

Although jQuery's XPath support is limited, theW3C's XPath Specification may still be useful for those wanting to learn more about the variety of possible XPath selectors:

http://www.w3.org/TR/xpath

The TopXML site provides helpful charts of axes, node tests, and functions for those wanting to learn more about XPath:

http://www.topxml.com/xsl/XPathRef.asp

The Microsoft Developer Network website has information on XPath syntax and functions:

http://msdn2.microsoft.com/en-us/library/ms256115.aspx

John Resig, et al., the official jQuery blog posts announcements about new versions and other initiatives among the project team, as well as occasional tutorials and editorial pieces.

http://jquery.com/blog/

Karl Swedberg, Jonathan Chaffer, Brandon Aaron, et al. are running a blog for jQuery tutorials, examples, and announcements:

http://www.learningjquery.com/

Jack Slocum, the author of the popular EXT suite of JavaScript components writes about his work and JavaScript programming in general:

http://www.jackslocum.com/blog/

Dustin Diaz blog features articles on web design and development, with an emphasis on JavaScript:

http://www.dustindiaz.com/

Jonathan Snook's general programming/web-development blog:

http://snook.ca/

Three sites by Christian Heilmann provide blog entries, sample code, and lengthy articles related to JavaScript and web development:

http://www.wait-till-i.com/

http://www.onlinetools.org/

http://icant.co.uk/

Jeremy Keith's blog picks up where the popular DOM scripting book leaves off—a fantastic resource for unobtrusive JavaScript:

http://domscripting.com/blog/

Stuart Langridge experiments with advanced use of the browser DOM:

http://www.kryogenix.org/code/browser/

A List Apart explores the design, development, and meaning of web content, with a special focus on web standards and best practices:

http://www.alistapart.com/

Chris Campbell, Kevin Hale, and Ryan Campbell started a blog that provides valuable information on many aspects of web development:

http://particletree.com/

Scott Andrew LePera's weblog about JavaScript quirks, caveats, odd hacks, curiosities and collected wisdom. Focused on practical uses for web application development:

http://jszen.blogspot.com/