... before HTML5 came on the scene, you already know a lot of HTML5. This also means that much of HTML5 works in both old and new browsers; being backward compatible is a key design principle of HTML5 ... The HTML5 details, summary, menu, command, and keygen elements.n The HTML5 canvas element, which allows you to draw graphics (and even create games) with JavaScript.n The HTML5 ... chap-ters and a summary of the topics covered.What is HTML5? It helps to know some basics about the origins of HTML in order to understand HTML5. HTML began in the early 1990s as a short document...