Processing's support for SVG is patchy. You should probably just report the bug at https://github.com/processing-js/processing-js/issues/new, and then use a PNG copy instead.
NB: renders OK on Firefox 35.
Edit: reported for you. https://github.com/processing-js/processing-js/issues/137
GoToLoop at the above link says that your problem with mousepressed
is caused by the fact that to avoid name collisions in JS, the boolean mousepressed
is called __mousePressed
in JS. They recommend that you use Java syntax to code your app and have it automatically translated into JS, to avoid these gotchas.
Result: just update Chrome, which you've probably done anyway now.