I started with Using Processing on the Web and Processing.js Quick Start – Processing Developer Edition tutorials. They offered a quick start for first experiments. For first tests just needed to download Processingjs library and start writing the code (based on examples) to my own computer hard disk (no server needed) with Notepad++ editor. Double-clicking the HTML page file made my browser (Firefox) to display the page and run the code in it.
I did also some initial testing with sketchpad, which is a open studio for individuals learning to sketch beautiful code on the web canvas. Studio SketchPad was named after the two web technologies on which the application is built: the Sketch from Processing and the Pad from EtherPad.
Whether you’re an advanced Processing developer or completely new, whether you’re a pro with web technologies or just getting started, Processing.js bridges the gap between these two powerful technologies.