Pluginweb.Net

While this is not strictly Ajax or JavaScript related, it is noteworthy to point out that Sitepoint just released a HTML reference that is quite handy to have around if you wonder if what you are building is really HTML or just tagsoup.

Good HTML references are really hard to come by, either they are just listings, like W3schools.com or terribly outdated. Sitepoint have done quite a good job in listing all the HTML elements and categorizing them into different use cases. There is also a list of deprecated elements and attributes to avoid (which could be considered dangerous to still bring up as some of them are too handy to simply add to solve an issue) and a Microformats primer.

We know for a fact that other portals/article sites are working on similar projects and consider it a really good way of flushing old and outdated tutorials on things as simple but important as markup out of the search engine result pages.

The reference also gives a legend of browser support, something that so so far was only available on the German SelfHTML reference.