[[File:Jsmess in Chromium.png|thumb|upright=1.43|JSMESS emulating a CPC6128 in Chromium 30 on Linux (with copious debug messages)]][[File:Jsmess firefox zoomed.png|thumb|upright=1.3|JSMESS in Firefox 24 (same rendering resolution but using page zoom to enlarge the CPC screen)]]'''JSMESS''' is a ("JavaScript MESS") was an ongoing JavaScript port of MESS (now simply called [[MESSMAME]] that runs in as of 0.162) for modern web browsers like Chrome and Firefox and . JSMESS is considered used by the Internet Archive to be make their Historical Software Collection playable in its public beta stage right nowweb browsers. Since MAME 0.168 (released in November 2015), JSMESS is no longer necessary as MAME can compile to JavaScript (using Emscripten's emmake command) out of the box.[http://mamedev.org/releases/whatsnew_0168.txt]
==History and development roadmap==
The JSMESS project was originally proposed in a [http://ascii.textfiles.com/archives/3375 October 2011 blog post ] by Jason Scott (of [http://www.textfiles.com and The Internet Archive in October 2011/ textfiles.com], the [http://asciiwww.textfilesarchiveteam.comorg/archivesArchive Team], and [http:/3375/archive.org/ The Internet Archive] ). The idea was to have a system for preservation of old computers and game consoles that runs directly in the web browser without any plugins.
Initial progress was slow because the Emscripten transcompiler had to be fixed and improved during development. In 2013, JSMESS reached a fairly usable state and was declared to be in public beta.
Also, keymapping and a virtual keyboard on the screen are planned for JSMESS, although in principle you should already be able to create keymaps in MESS and use them with JSMESS.
JSMESS development is heading headed toward its 1.0 versionrelease. The [https://github.com/jsmess/jsmess/wiki/JSMESS-v1.0-Systems list of systems] that are supposed to be officially supported by 1.0 also includes the CPC464/664/6128 (although the printer is erroneously listed as the program medium for the CPC on the list).
==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.
==Features and status==
As of October 2013, sound only works in Firefox and not in Chrome/Chromium. Emulation speed in Firefox is better than in Chrome, presumably because Firefox has better support for Emscripten's asm.js-based JS code. Internet Explorer 10 was supposedly supported very well by earlier versions of JSMESS with up to [https://github.com/jsmess/jsmess/wiki/Status 100% emulation performance] (including working sound) but the current JSMESS exits with an Emscripten error in IE 10. The joystick is mapped to Alt and the arrow keys by default. The development version of JSMESS at archive.org also has support for USB gamepads but no sound.
==Usage on web pages and CPC CPC6128 demo page==
Right now the way to get JSMESS running on a page is to edit the top of messloader.js so that <tt>gamename</tt> points to a DSK file for drive A.
Also, you need to provide the zipped ROM file. Note that the ROM file cpc6128.zip as on the demo page below also needs to contain the AMSDOS ROM from cpc464.zip because unlike regular MESS, JSMESS only loads a single ROM ZIP file per machine.
This [http://mdoege.github.io/jsmess/ JSMESS CPC demo page] (with the SubHunter ''[[Sub Hunter]]'' disc in drive A) also has a ZIP file download of the build with the JS, ZIPs, and HTML. Resolution is set to MODE 1 (384x272), but you can either set a higher resolution in messloader.js or use the zoom functionality of the browser to get a larger picture.
==Links==
*[http://jsmess.textfiles.com/ Official site];General info*[https://github.com/jsmess/jsmess GitHub page with source codeOfficial site] (without any CPC makefiles right now)*[httpshttp://githubarchive.comorg/mdoegedetails/jsmess Forkinternetarchivecelebration20131024?start=2544 Video of Jason Scott presenting JSMESS and the Historical Software Collection] with added CPC6128 makefilesat the Internet Archive*[http://mdoegearchiveteam.githuborg/index.io/jsmess/ CPC6128/SubHunter demo php?title=Javascript_Mess Archive Team wiki page]about JSMESS
*[http://en.wikipedia.org/wiki/Jason_Scott_Sadofsky Jason Scott], initiator of the project, at Wikipedia
;Code
*[https://github.com/jsmess/jsmess GitHub source code repository] (without any CPC makefiles right now)
*[https://github.com/mdoege/jsmess GitHub fork] with added CPC6128 makefiles
;Demos
*[http://mdoege.github.io/jsmess/ CPC6128/Sub Hunter demo page]
*[https://archive.org/details/consolelivingroom The Console Living Room] at the Internet Archive
[[Category:Emulator]]