Javascript is also a supported target for libsodium, through Emscripten. The Javascript file size (minified/gzipped, with most operations including password has

Javascript is also a supported target for libsodium, through Emscripten. The Javascript file size (minified/gzipped, with most operations including password hashing using scrypt) is 136K. TweetNaCl.js doesn't have the same features set, but it is tiny, has been written in Javascript, is easy to use, well-documented, and well-maintained. This is what Minilock uses. It is a perfect fit for this kind of applications.