Changes
[[File:Jsmess in Chromium.png|thumb|upright=1.3|JSMESS emulating a CPC6128 in Chromium 30 on Linux (with copious debug messages)]]
[[File:Jsmess firefox zoomed.png|thumb|upright=1.3|Running JSMESS in Firefox 24 (same rendering resolution but using page zoomto enlarge the CPC screen)]]'''JSMESS''' is a ("JavaScript translation 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 used by the Internet Archive to 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/ textfiles.com] , the [http://www.archiveteam.org/ Archive Team], and [http://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.
==Building from source==
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.
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 ''[[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==
;General info*[httphttps://jsmess.textfilesgithub.com/ jsmess/jsmess Official site]*[http://archive.org/details/internetarchivecelebration20131024?start=2544 Video of Jason Scott presenting JSMESS and the Historical Software Collection] at the Internet Archive*[http://archiveteam.org/index.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/SubHunter Sub Hunter demo page]*[httphttps://en.wikipediaarchive.org/wikidetails/Jason_Scott_Sadofsky Jason Scottconsolelivingroom The Console Living Room], initiator of the project, at Wikipediathe Internet Archive
[[Category:Emulator]]
