What is Processing?
The Processing language was originally created at MIT as part of the Media lab and Aesthetics and Computation group. They needed a way to bridge the gap between software developers, artists, data visualizers, etc., and to do so in a way that allowed new programmers (or non-programmers) to do complex visual work easily. Processing was built using Java, and can be thought of as a simplified Java, with a simplified Java API for drawing and graphics.
What does Processing bring to the web?
How much work is it to learn Processing?
Ways to Use Processing.js
Below we discuss the various methods for using Processing.js in your web pages.
Writing Pure Processing Code
This is the preferred method for using Processing.js, and has been dealt with at length in the Processing.js for Processing Devs quick start guide. To summarize:
Download Processing.js from here