I highly recommend PHP for this one. But, a word of caution for anyone who does, be aware that the modulus operator (%) only handles integers up to 32-bits in size. For this project, consider using bcmod() .

There are a couple of ways you can do this, but I think the most useful solution, and the one with the most real world applications (where you can't rely on Firefox add-ons or Chrome) may be found in the following link: http://www.linuxquestions.org/linux/answers/Security/Decoding_obfuscated_javascr...