examples

html

W3Schools, HTML Tutorial.
Codecademy, HTML & CSS.
DevTips, HTML5 Basics - Tags [video]

css

W3Schools, CSS Tutorial.
LearnLayout, Learn CSS Layout.

dom

Jonathan Robie, What is the Document Object Model?, W3C REC-DOM-Level-1.
DevTips, HTML5 Basics - The DOM [video].
Marijn Haverbeke, Eloquent JavaScript, The Document-Object Model (Chapter 13).

javascript

W3Schools, Javascript Tutorial.
Marijn Haverbeke, Eloquent JavaScript Chapters 1, 2, 3, 4, 5, 6, 8.
David Flanagan, JavaScript: The Definitive Guide.
Codecademy, Make an Interactive Website.
Richard Bovell, Javascript Objects in Detail.
Richard Bovell, JavaScript Variable Scope and Hoisting Explained.
W3Schools, JSON Tutorial.
JSHint, JSHint Code Quality Tool, available in most editors/IDEs.

event handling

Marijn Haverbeke, Eloquent JavaScript, Handling Events (Chapter 14).
David Flanagan, JavaScript: The Definitive Guide, Chapter 17, Handling Events.
QuirksMode, Introduction to Events.
Javascript Kit, Understanding "event handlers" in JavaScript.
Marijn Haverbeke, Eloquent JavaScript,
HTTP (Chapter 17), Forms and Form Fields (Chapter 18).

storage

W3Schools, HTML5 Local Storage.
HTML5 Rocks, HTML5 Features - Storage.

animation & graphics

W3Schools, CSS3 Animations.
John Galantini, Aaron Kitney, et al, 22 stunning examples of CSS3 animation.
W3Schools, HTML5 Canvas.

xpath

W3C, XML Path Language (XPath) Version 1.0.
W3Schools, XPath Syntax.

html5 editors

Adobe, Brackets.
github, Atom.