examples

html

html5 dom

DevTips, HTML5 Basics - The DOM [video].
Marijn Haverbeke, Eloquent JavaScript, The Document-Object Model (Chapter 13).

css

CSS-Tricks, CSS Guides.
Lea Verou, CSS Secrets
Dave Shea, CSS Zen Garden.
CSS-Tricks, Guide to Flexbox
nana, Ryan Yu, CSS selectors cheatsheet.

javascript

Marijn Haverbeke, Eloquent JavaScript Chapters 1, 2, 3, 4, 5, 6, 8.
David Flanagan, JavaScript: The Definitive Guide.
Richard Bovell, JavaScript Variable Scope and Hoisting Explained.
json.org, Introducing JSON.
DigitalOcean, Introduction to JSON.
JSHint, JSHint Code Quality Tool (available in most editor/IDEs).

event handlers

storage

W3Schools, HTML5 Local Storage.
Mosilla Web Docs, Window: localStorage property.

animation & graphics

xpath