In order to build libmp3lame.js, make sure you have emscripten installed. Then simply run "make", and the build process will download the lame source file, extract it, and build the JavaScript version of libmp3lame.
Alternatively, the dist subdirectory contains a minified, ready-to-use version of libmp3lame.js.
Andreas Krennmair ak@synflood.at
libmp3lame.js is published under the license terms as lame.