One would assume since you, the reader, are coming from a Flash development background, a moment should be taken to talk about frame rates or frames per second when developing HTML5 applications. Since every asset in Flash applications is based on the timeline model, calculating how many frames of that timeline are displayed every second is a pretty simple calculation. However, all the technologies that make up HTML5 development do not rely on the use of a timeline during runtime. Therefore calculating the frames per second or FPS value of a webpage is not always an accurate measure of performance of your HTML5 projects.
Tip
Our CSS 3D Transform example found in the chapter code examples includes the use of a great piece of JavaScript called Stats.js to monitor the frames per second as well as the ms. Stats.js is a open source project that can be found at https://github.com/mrdoob/stats.js.