Not if it's a generic webpage that is viewed in Safari. If I'm not terribly much mistaken, that's the whole point of this project-- it gets around 3.1.1 by using offline support in Safari. After all, Processing.js is not technically pure JavaScript, and so it would fall subject to 3.1.1 were it not for this method.
Slightly off-topic, but does anyone know what keeps this IDE from working in Firefox 3.5?