emscripten compiles "regular" C/C++ projects to JavaScript via LLVM. This is how marvels such as PCE.js (A Mac Plus/IBM PC emulator in the browser) can exist. This evening, I've made a few attempts at compiling a number of Tcl versions (from 8.6.1 back to 8.2, didn't get further) using emscripten. The steps for compiling are in theory easy and well-documented . However, emmake make fails every time in the Network code. It fails once when trying to solve "services" to port number (something that can easily be commented away) but also later on in the platform implementation of the socket command. It got too late, so I gave up. Anybody who wants to continue? This should provide an alternative implementation of Tcl in the browser. EF