Browser compatibility tables for HTML and CSS features etc
"The leading independent resource for .NET developers"
Excellent site with examples and explanation
Articles on jQuery, AJAX etc
HTML to text
See what a web page looks like in a text-only browser
Tutorials and FAQs on web programming
Framework for developing mobile-friendly websites
Browser compatibility tests for various standards
Open-source framework for building desktop-class web applications
guide to portals and search engines
Detailed page validator covering accessibility, broken links etc.