SpiderMonkey is the Mozilla's C's JavaScript engine - they got one in Java, called Rhino and one in JavaScript that I don't remember its naming.

SpiderMonkey is used on the Firefox browser, so a millions of people got it handy.

It's fairly easy to make a graphical interface to allow any end user to copy or save the data to a file.

Everywhere you have to update your techniques when new malwares appear.
The better your heuristic, the less you have to update.