A simple algorithm for public-key encryption?

Does anyone know anything about public-key encryption? Specifically, is there any efficient, easy-to-implement algorithm for generating a public/private key pair and using said keys to encrypt and decrypt data? (It doesn't have to provide a particularly high level of security, but I'd need to implement it simultaneously in multiple languages, of which one is JScript/JavaScript, so simplicity is key.)

I'm kind of assuming the answer is no, but I figured it doesn't hurt to ask. Thanks in advance. :-)