[[File:Jsmess in Chromium.png|thumb|upright=1.1|JSMESS emulating a CPC 6128 in Chromium 30 on Linux]]
MESS has also recently been ported to JavaScript using the C/C++-to-JS transcompiler Emscripten; this port is called [http://jsmess.textfiles.com/ JSMESS]. So far Out of the box only a small selection of MESS machines are supported can be immediately compiled to JavaScript from the JSMESS package. Compiling MESS in JSMESS—the main problem its entirety would create a JavaScript file that is finding far too big for web browsers to handle. So one has to find out which parts of MESS modules are really needed for a given architecture machine and creating the create Makefiles accordingly, although with that subset. (JSMESS now also includes scripts that scan for dependenciesautomate this task. ) It is recommended to build JSMESS modules on Linux (which also makes it easier to install the dependencies for Emscripten).
A [https://github.com/mdoege/jsmess JSMESS fork] that includes the necessary Makefiles to build the CPC 6128 version exists.