A List Apart Magazine, according to its website, explores the design, development, and meaning of web content with a special focus on web standards and best practices. Its articles discus everything from pixels to prose and coding to content, in each of six categories: code, content, culture, design, process and user science, making it one of the leading sources for web design information on the Web.
SitePoint is an international online media company and information provider targeting the Web professional market, specifically Web Developers and Designers. It covers topics from “before you code” and “design and layout” to Client- and Server-side coding, site strategy and marketing. It also offers a number of reference materials, including references on CSS, HTML and Java script.
W3Schools is a free online resource created to help train web designers and developers. It features tutorials, guides and examples. It includes user content and the best links aggregated from around the web.
Learning jQuery is a multi-author blog providing tutorials, demos, and announcements about jQuery. Tutorials are available for all skill levels, and each entry is categorized by level of difficulty.
jQuery for Designers, as the name implies, is dedicated to explaining jQuery design. It was created to serve the design community and to “bridge the barrier to the funky interaction stuff.” Specifically, its purpose is to teach designers with very little programming experience how to include additional effects within pages and to understand what they are adding.
W3validator tests the markup of Web documents, including html and xhtml. It conforms to International Standard ISO/IEC 15445—HyperText Markup Language, and International Standard ISO 8879—Standard Generalized Markup Language (SGML) – which basically means that in addition to W3C recommendations, it can validate according to these ISO standards. You can also validate your css here.