All the HTML elemens you can use. There is more than just a div :)
The web accessibility basics
The absolute web accessibility basics every web developer should know about.
Introduction to HTML
In just 4 hours, learn the basics of HTML5 and start building & editing web pages.
A curated list of awesome Canvas examples, related articles and posts.
This specification defines a big part of the Web platform, in lots of detail.
This tool is checking your markup if it complies with the specification and will show you possible errors.