Notes from an Intro to Canvas, 8bitrocket, DevCon5

Firefox Canvas performance got really bad six months ago, slowly coming back now

Retained mode (Flash, DOM) versus Immediate mode (Canvas)

They still use Modernizr.js to test for Canvas support

They end up creating (minimal) object system and re-rendering the whole scene at each frame

You can do much of this with CSS, but for developers coming from other technologies, this is so much easier