The Bitcoin Extended Public Key Converter repository can be found at https://github.com/jlopp/xpub-converter
This logic is also available as an npm module via https://github.com/ExodusMovement/xpub-converter
bip32: https://github.com/bitcoinjs/bip32
bs58check: https://github.com/bitcoinjs/bs58check
tiny-secp256k1: https://github.com/bitcoinjs/tiny-secp256k1
Twitter Bootstrap: http://getbootstrap.com/