The Damm algorithm is an amazingly useful algorithm. I put together a Base32 version that I use for checking passwords that users enter [1]. It is only in C and PHP right now - I need to get around to porting it javascript [2].<p>[1] <a href="http://www.tillett.info/2014/06/12/base32-implementation-of-the-damn-error-detection-algorithm-in-c/" rel="nofollow">http://www.tillett.info/2014/06/12/base32-implementation-of-...</a><p>[2] <a href="https://github.com/DanielTillett/Damm32" rel="nofollow">https://github.com/DanielTillett/Damm32</a>