如何运行不受信任的代码服务器端?

I'm trying to run untrusted javascript code in linux + node.js with the sandbox module but it's broken, all i need is to let users write javascript programs that printout some text. No other i/o is allowed and just plain javascript is to be used, no other node modules. If it's not really possible to do, what other language do you suggest for this kind of task? The minimal feature set i need is some math, regexes, string manipulation, and basic JSON functions. Scripts will run for let's say 5 seconds tops and then the process would be killed, how can i achieve that?I'm trying to run untrusted javascript code in