zee.js
zee.js is a port of zlib, a very useful compression library (used in gzip) to JavaScript, by compiling the zlib C code with Emscripten.
zee.js is zlib licensed, just like zlib.
Usage
Zee.compress and Zee.decompress are the relevant functions. See test.js for an example.
There is also a worker version, zee-worker.js. See zee-client.js for usage.