In our class we used the Khan Academy's Computer Science module, which has its own version of Processing.js
Processing.js is the JavaScript implementation of the Processing programming language. Designers, artists use Processing for professional finished work. Many universities like UCLA, RISD, CMU use Processing in their classrooms to teach programming. See some student samples at openprocessing.org
For more on introducing students to programming using Processing, read my article
Building with Code (Written for my pledge for CSEd week Dec 9-15, 2012 )
CLASS projects
Optional projects for LASD students
Instructions
Math Class project (done at Santa Rita)
Math programs to calculate Areas and Perimeters, temperatures
Virtual Robot