At first, Emscripten sounds like the punch line to a tech joke: a compiler that converts C/C++ code into Asm.js, a subset of JavaScript that can then run via a Web browser or in the Node.js framework.
But it's no joke. Emscripten and Asm.js (the latter started as a Mozilla research project) have been making major strides since their introduction. The latest step up is an Emscripten revision that replaces the original compiler core with one derived from LLVM, a compiler technology framework used mainly for C/C++ but in theory capable of supporting many other languages.