Ok, this is a really simple one. More a proof of concept. I haven't really given much thought to the security implications and it might be mean to cute cats and children so you've been warned. It uses the Java Nashorn engine which I think requires you to use the JDK. I can't really find much information on that though. I'm not sure why it would only be included in the JDK and not the JRE but I've found a few posts that seem to indicate that.
Provided is a single function js:exec(). The first argument is a string to execute and any subsequent arguments are placed in a global variable accessible to the script called values. Right now it only takes strings but in the future I might extend it to take resources that would be downloaded or loaded from the local file system. Any feedback would be appreciated.