Former ProcessingJS mode (Processing 1.5) that became JavaScript mode (Processing 2.0 beta) that has now been moved out of the Processing IDE.
JavaScript Java Processing HTML
Latest commit 8204f3c Oct 8, 2015 @fjenett test build

README.md

Processing JavaScript Mode

This is the former ProcessingJS tool (for Processing 1.5) that became Processings internal JavaScript mode (until 2.0 beta 8) and has now been moved out of the Processing IDE.

Use [Mode menu] --> Add Mode ... to install into your PDE.

Tested with Processing 2.2.1 and 3.0a5