Whit Jackson produced one which seems to become built making use of HTML/Javascript (GitHub connection). He also had a web site in which you could generate the addresses shopper side, nonetheless it seems to generally be down now. BTC addresses use Base58 (like Base64 but without comparable character: IOl0+/) and https://rylantivhr.blogsidea.com/35966628/the-smart-trick-of-vanity-eth-address-generator-that-nobody-is-discussing