==Building from source==
Out of Unlike a normal port (that is translated only once), the box JSMESS code is created by Emscripten directly from the MESS code every time you compile JSMESS. In the official version of JSMESS only a small selection of MESS machines can be immediately compiled to JavaScript from out of the JSMESS packagebox. Compiling Since compiling MESS in its entirety would create a JavaScript file that is far too big for web browsers to handle. So , one has to find out which parts of MESS are really needed for a given machine and create Makefiles with that subset. (JSMESS now also includes scripts that automate this task.)
It is recommended to build JSMESS modules on Linux which also makes it easier to install the dependencies for Emscripten. The basis for JSMESS is MESS 0.142 and a custom version of Emscripten.