Those sidesteppings are outlawed by the Chrome Web Store policies.
There are JS-in-JS interpreters out there. They're just not allowed. https://github.com/jterrace/js.js/ https://github.com/marten-de-vries/evaljs
In More malicious extensions in Chrome Web Storejterrace
js.js
JavaScript2012–2023
jterrace / js.js
js.js
js.js: A JavaScript JavaScript interpreter
19Distinct people
21Mentions
0Explicit recommenders
1.1KGitHub stars
What to know before exploring
What it is
js.js: A JavaScript JavaScript interpreter
GitHub
Where it is used
No documented product use was verified in the last source check.
What people are saying
No recommendation phrase was found in the indexed comments.
No classified warning is attached to this page. Read the discussions before treating silence as approval.
Also in these discussions
- mozilla/narcissus · linked in 2 of the same discussions
Mentioned in the same Hacker News threads. That is not proof they are substitutes.
This week on Hacker News
Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 3:56:07 PM UTC.
No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.
Mentions over time
HN mentions by year21 dated mentions
Observed mentions: 2012-01-02 22:21:46 UTC to 2023-06-01 17:14:33 UTC.
Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.
View mention counts and date ranges
| Period | Start (UTC) | End (exclusive, UTC) | Mentions | Submissions | Comments |
|---|---|---|---|---|---|
| 2012 | 2012-01-01 00:00:00 UTC | 2013-01-01 00:00:00 UTC | 2 | 1 | 1 |
| 2013 | 2013-01-01 00:00:00 UTC | 2014-01-01 00:00:00 UTC | 7 | 0 | 7 |
| 2014 | 2014-01-01 00:00:00 UTC | 2015-01-01 00:00:00 UTC | 4 | 1 | 3 |
| 2015 | 2015-01-01 00:00:00 UTC | 2016-01-01 00:00:00 UTC | 3 | 0 | 3 |
| 2016 | 2016-01-01 00:00:00 UTC | 2017-01-01 00:00:00 UTC | 1 | 1 | 0 |
| 2017 | 2017-01-01 00:00:00 UTC | 2018-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2018 | 2018-01-01 00:00:00 UTC | 2019-01-01 00:00:00 UTC | 2 | 1 | 1 |
| 2019 | 2019-01-01 00:00:00 UTC | 2020-01-01 00:00:00 UTC | 1 | 0 | 1 |
| 2020 | 2020-01-01 00:00:00 UTC | 2021-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2021 | 2021-01-01 00:00:00 UTC | 2022-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2022 | 2022-01-01 00:00:00 UTC | 2023-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2023 | 2023-01-01 00:00:00 UTC | 2024-01-01 00:00:00 UTC | 1 | 0 | 1 |
From the project README
An excerpt from the repository, fetched Nov 13, 2026.
Read the project’s introduction
js.js is a JavaScript interpreter in JavaScript. Instead of trying to create an
interpreter from scratch, SpiderMonkey is compiled into LLVM and then
emscripten translates the output into JavaScript.
Demos
See several running demos here.
Paper
Academic paper to appear at
WebApps 2012 located
here.
Status
The compiled version of js.js is 3MB and only 594KB after gzip compression.
Using the Sunspider benchmark, the interpreter is about 200 times slower
than Spidermonkey's native interpreter with the JIT compiler turned off. More
optimizations and benchmarks are coming soon.
Example Use
Here is an example of how to use the API:
var jsObjs = JSJS.Init();
var rval = JSJS.EvaluateScript(jsObjs.cx, jsObjs.glob, "1 + 1");
var d = JSJS.ValueToNumber(jsObjs.cx, rval);
window.alert(d); //2
JSJS.End(jsObjs);
More examples are available in the examples directory.
Files
The following files are located in the src directory.
File
Description
js.O0.js
Command-line JS shell, no optimizations
js.O0.min.js
Command-line JS shell, no optimizations, closure compiled
js.O1.js
Command-line JS shell, O1 optimizations
js.O1.min.js
Command-line JS shell, O1 optimizations, closure compiled
js.O2.js
Command-line JS shell, O2 optimizations
js.O2.min.js
Command-line JS shell, O2 optimizations, closure compiled
libjs.O0.js
JSAPI shared library, no optimizations
libjs.O0.min.js
JSAPI shared library, no optimizations, closure compiled with js.js wrapper
libjs.O1.js
JSAPI shared library, O1 optimizations
libjs.O1.min.js
JSAPI shared library, O1 optimizations, closure compiled with js.js wrapper
libjs.O2.js
JSAPI shared library, O2 optimizations
libjs.O2.min.js
JSAPI shared library, O2 optimizations, closure compiled with js.js wrapper
jsjs-wrapper.js
js.js wrapper API to make using the JSAPI easier
To run the shell, you want to run one of these:
js js.O2.min.js -e "print('hello');"
node js.O2.min.js -e "print('hello');"
To include the API in your website, include the minified libjs like this:
<script type="text/javascript" src="libjs.O2.min.js"></script>
Alternatively, you can use the wrapper script directly with a non-minified
version (useful for debugging and modifications):
<script type="text/javascript" src="libjs.O2.js"></script>
<script type="text/javascript" src="jsjs-wrapper.js"></script>
Read the full README on GitHubWhat Hacker News says
21 sourcesDefinitely not the first JS VM compiled to the browser. Aside from JSC as another comment mentioned, there was also js.js which is SpiderMonkey compiled to JS (around 2012!),
https://github.com/jterrace/js.js/
This shouldn't be surprising - many VMs have been compiled to the Web, like Lua, Python (both CPython and PyPy!), etc., and JS is just another VM.
In QuickJS JavaScript EngineThere's a bunch: https://github.com/jterrace/js.js/
In A pure JavaScript implementation of Git for Node and browsersIt's not as impossible as it sounds.
There are many JS engines which are extremely small compared to the big guys used in browsers. Most of them tend to grab a subset of the language and implement that.
For example, the creators of nginx created their own specialized engine called nginScript that runs JS for their stuff https://www.nginx.com/resources/wiki/nginScript/
There is even a javascript interpreter written in javascript which can be a good starting point to learn a bit how it works https://github.com/jterrace/js.js/
In Microsoft Edge's JavaScript engine to go open-sourceNo, because V8 has no interpreter (although they are working on one: https://code.google.com/p/v8/issues/detail?id=4280), only JIT, and JIT doesn't run inside asm.js.
asm.js-compiled JavaScript engine has been done already: https://github.com/jterrace/js.js.
In JavaScript runtime for Unreal EngineThe footer says that if you want a real "Javascript to Javascript interpreter", to see js.js[0], which is a JS interpreter written JS; where the satirical js2js is a JS-to-JS compiler, something different. If you want a real JS to JS compiler, see Google's "Closure Compiler"[1].
[0]: https://github.com/jterrace/js.js/
[1]: https://developers.google.com/closure/compiler/ / https://github.com/google/closure-compiler
In Js2js: A revolutionary open-source compiler from JavaScript to JavaScriptAsk HN: What options are there for executing untrusted code in Node.js?
Over the past couple of weeks while prototyping various ideas I've kept on running into a hurdle when it comes to trying to run untrusted JavaScript code in Node.JS.
One solution I found early on was Sandbox (http://gf3.github.io/sandbox/), which seems to be fairly safe security wise, but doesn't offer much else.
Node.JS also has a vm module (http://nodejs.org/api/vm.html), but it it is 'Unstable'.
I've also come across sandboxed-module (https://github.com/felixge/node-sandboxed-module), however I can't figure out what it actually does, and also js.js (https://github.com/jterrace/js.js), but it's much too slow to be of much use.
So, does anyone else know of any other solutions?
4 points · Open discussionjs.js¹? Also, take a peek at repl.it if you haven't already
[1] https://github.com/jterrace/js.js/
[2] http://repl.it/languages
In Show HN: Breach – A modular browser built on Chromium and Node.jsThis one is actually legitimate. Saw it on HN a while ago, really funny:
https://github.com/jterrace/js.js/
In What 4chan thinks of HNSecurity. When you want to run untrusted modding code.
It's hard to sandbox python or lua and block I/O and all system calls. 1 mistake and player computers are compromised.
Even with JS in browser you can't just eval(), you need sandboxing like https://code.google.com/p/google-caja/ or https://github.com/jterrace/js.js/ (200 times slower than js).
In Game Programming Patterns – BytecodeThere are already several PC emulators in JS, and there are at least two Javascript interpreters in JS:
This one is Spidermonkey compiled with Emscripten: https://github.com/jterrace/js.js/
And this one is a test-bed for new JS language features (or at least meant to be - don't know how far along it is): https://github.com/mozilla/narcissus
In Vim.js - JavaScript port of VimOne problem is that you can't do runtime code generation with Emscripten. V8 has no interpreter, so you would need a different JavaScript engine.
JavaScript engines can be run using asm.js. https://github.com/jterrace/js.js is a SpiderMonkey port to Emscripten (with JIT disabled).
In On Asm.jsI'm waiting for a JavaScript interpreter written in Javascript.
Edit: It's already here :)
https://github.com/jterrace/js.js/
In Java Virtual Machine in pure Node.jsShowing the 15 most recent of 21 sources. Enable JavaScript to search and browse every indexed mention.