Coco A CoffeeScript dialect that aims to be more radical and practical, also acts as a test bed for features that get imported in CoffeeScript.
LiveScript is a fork of Coco that is much more compatible with CoffeeScript, more functional, and with more features.
IcedCoffeeScript A CoffeeScript dialect that adds support for await and defer keywords which simplify async control flow.
Parsec CoffeeScript CS based on parser combinators. The project's aim is to add static metaprogramming (i.e. macros + syntax extensibility) to Coffee Script (CS), similar to how Metalua adds such features to Lua. The resulting compiler, once merged with the official compiler, should be usable as a drop-in replacement for it.
Contracts.coffee A dialect of CoffeeScript that adds built-in support for contracts.
Uberscript, a CoffeeScript fork that adds type annotations which are compiled to Google closure compiler type annotation comments.
ToffeeScript A dialect of CoffeeScript that support Asynchronous Syntax and Regexp operator =~
Caffeine A dialect of CoffeeScript that support packages and classes import, useful for browser applications
heap.coffee A dialect of CoffeeScript that offers a C-like type system with manual memory management
pogoscript language that emphasises readability, handles async control flow nicely, is friendly to domain specific languages and compiles to regular JavaScript
LispyScript A JavaScript with Lispy syntax and Macros. ○
wisp A homoiconic JavaScript dialect with Clojure syntax, S-expressions and macros. Aims to be rich subset of Clojure(Script) that seamlessly interops with both Clojure(Script) and JavaScript. ○
Hot Cocoa Lisp A Lisp-like language that compiles to JavaScript. ○
ki Clojure-like syntax, mori's immutable data structures in a few sweet.js macros. Can be intermixed with JavaScript. ○
jisp A JS-native and axiomatic Lisp that focuses on the core ideas of code-as-data, S-expressions, and macros, introducing as few new concepts as possible. ○
Ham looks very similar to JavaScript at first, but offers (hopefully) many useful features
GorillaScript Compile-to-JavaScript language designed to empower the user while attempting to prevent some common errors, offers Macros and optional Typing
LiteScript Literate, highly-readable, type annotated, imperative language that compiles to JavaScript.
ColaScript similar to Dart, CoffeeScript, Python and PHP
Taijilang a customizable and extensible language with dynamic parser and meta language.
MoonScript MoonScript is a dynamic scripting language that compiles into Lua. The syntax of MoonScript has been heavily inspired by the syntax of CoffeeScript.
Earl Grey An extensible language with pattern matching, hygienic macros and a syntax similar to Python.
Khepri Lightweight language that reworks Javascript's syntax to be better for untyped functional-style programming.
Spider Spider is a programming language that compiles to JavaScript (ES5 and ES6 targets). It takes the best ideas of Go, Swift, Python, C# and CoffeeScript.
CirruScript write JavaScript with indentations and polish notations, similar to S-Expression but with fewer parentheses.
Pallet Pallet is a innovative, modern programming language with a nice syntax, and optional functional programming and loose variable type checking.
TLC Tag Line Commands is a inline macro language for calling+formatting javascript/coffeescript/livescript json output into HTML.
Dojo Secure Framework for building secure mashups.
Local.js uses Web Workers to sandbox applications and a RESTful messaging protocol called HTTPL (HTTP Local) to communicate between them
Static typing
Some of the ones listed below are also statically typed, such as mobl, GWT, JSIL, NS Basic, and Haxe.
Dart by Google. C/Java-like syntax with optional typing.
TypeScript by Microsoft. Typed superset of JavaScript.
TeJaS from Brown PLT. Types for JavaScript (itself).
asm.js – subset of JavaScript that can be used as a low-level, efficient target language for compilers. Now included in Firefox.
JavaScript++ JavaScript superset with classes, type checking, among other features
MileScript [commercial] A strongly-typed language similar to C# and Java, but which compiles to JS. free for non-profit, educational use.
Mascara [commercial] Enhances JavaScript with powerful features like classes, namespaces and type-checking.
Roy tries to meld JavaScript semantics with some features common in static functional languages
Elm type-safe functional language that compiles to HTML, CSS, and JavaScript.
JSX a faster, safer, easier alternative to JavaScript
Este.js Google Closure written in CoffeeScript statically compiled to JavaScript (and much more).
Swym – statically typed, with type inference and generics
Typecast.js – JavaScript platform for statically typed variables without a custom compiler.
PureScript – a small, strongly typed programming language that compiles to JavaScript, featuring extensible records and effects, and type classes.
AtScript by Google – project to improve JavaScript by adding type annotations and other features on top of TypeScript. Now defunct, will be merged into Microsoft's TypeScript.
Flow by Facebook - static type checker for JavaScript, supports optional types and null checks
Synchronous to Asynchronous JavaScript Compilers (CPS)
Streamline.js Uses underscore (_) to stand for callbacks. This fork preserves line numbers for debugging.
mobl The new language for programming the mobile web.
NarrativeJS JavaScript extension with asynchronous futures and promises.
jwacs JavaScript With Advanced Continuation Support.
Wind.js Wind.js is an advanced library which enable us to control flow with plain JavaScript for asynchronous programming (and more) without additional pre-compiling steps.
Continuation.js A lightweight JIT compiler for simplifying asynchronous JavaScript programming with no runtime dependences. It supports both Node.js and browser-side JavaScript and is compatible with CoffeeScript (also TypeScript, and any other scripts compile to js).
Kal makes asynchronous programming easy and clean by allowing functions to pause and wait for I/O, replacing an awkward callback syntax with a clean, simple syntax
JSPipe provides JavaScript primitives to write async code without callbacks or chained functions. Inspired by Goroutines and Channels found in Go and in Clojure. For Web and NodeJS. ES5 and ES6.
promiseLand promiseLand is a very promising Language. It includes ES5 strict mode, uses the * dereferencing operator to access promise results and introduces additional features designed to let you focus on your program logic. Such as dynamic typesafety, frame addressing, generic load and safe features.
Objective-J Shares with JavaScript the same relationship that Objective-C has with the C programming language: that of being a strict, but small, superset.
Mochiscript Object-oriented JavaScript with syntactic sugar. Released as a Ruby gem.
Six Six is a language super-set of JavaScript that enables new syntactic features from the 6th edition of ECMAScript to be used, through a transpiler, in your scripts today.
Bulbul Python3 to JavaScript/ES6/ES7 compiler. Apparently the only Python-to-JS compiler intended to provide support for AngularJS, React, Aurelia and other modern JS libs.
pythonscript Python compiled to readable JavaScript using the AST. (proof of concept)
Rusthon Integrates several python to js methods into one project. Very Active. Not only for JS & Py, but also Go, C, Nim, etc.
PyPyJS PyPy. Compiled into JavaScript using Emscripten. JIT-compiling to JavaScript at runtime.
Erlang
Shen is the first and yet smallest Erlang JavaScript Compiler based on Erlang AST. It allows you to translate Elixir, Joxa, Lol and Erlang programs to JavaScript with erlc. JavaScript/OTP subset. Has node npm package called erlang-shen-js.
LuvvieScript a browser-based dom-scripting language that is a strict sub-set of Erlang which is AST-to-AST transpiled to JavaScript (code )
Perl
Perlito Project to compile Perl 5/6 to JavaScript, Ruby, SBCL, and Go.
Java/JVM
GWT Google Web Toolkit, compiles Java to JavaScript.
Java2Script Eclipse Java to JavaScript compiler plugin and JavaScript version of SWT.
Blue Storm F# to JavaScript (and some other languages).
JScriptSuite .NET to JavaScript compiler (cross browser API, client site controls and components).
DotNetWebToolkit Toolkit providing a .NET CIL to JavaScript transcoder and Visual Studio project/debugging integration
Netjs .NET to TypeScript and JavaScript compiler. It uses multiple stages to produce JavaScript for your web apps.
WootzJs C# to Javascript cross-compiler built on top of Microsoft Roslyn, which handles the complex process of converting your C# code into syntax trees with symbol information
Chlorinejs A fork of ClojureJS with a port of clojure.core library.
wisp A homoiconic JavaScript dialect with Clojure syntax, S-expressions and macros. Aims to be rich subset of Clojure(Script) that seamlessly interops with both Clojure(Script) and JavaScript. ○
Scriptjure Library for generating JavaScript from Clojure forms.
ki Clojure-like syntax, mori's immutable data structures in a few sweet.js macros. Can be intermixed with JavaScript. ○
jisp A JS-native and axiomatic Lisp that focuses on the core ideas of code-as-data, S-expressions, and macros, introducing as few new concepts as possible. ○
jmacro Quasi-Quoted JS that you can insert Haskell values into (there is also shakespeare-js for that purpose), but also supports a more Haskellish syntactic version of JavaScript.
Spiderbasic [commercial] SpiderBasic is new web client-side programming language based on established BASIC rules. Its main purpose is to allow development of very complex, windowed based web applications. It provides a large commandset to handle complex and reactive GUI, 2D games, and many more in a coherent manner.
Pascal
Smart Mobile Studio [commercial] Object Pascal to JavaScript compiler and Delphi like IDE that brings classes, inheritance, interfaces and more to JavaScript
Elevate Web Builder [commercial] Visual development tool for web applications that compiles standard Object Pascal source code into JavaScript
Go
Go2js Line-to-line translator from Go to JavaScript.
TARDISgo Compile Golang to Haxe (then on to JavaScript, Flash, Java, C++, C#, PHP, Python & Neko)
Multitarget
Haxe compiles to several platforms (C++, Flash, JS, Neko, PHP, Java, C#, Python).
Fantom Evolutionary object-oriented language emphasizing succinct and effective APIs (JVM, CLR, JS).
LZX (Laszlo XML) LZX is OpenLaszlo's declarative user interface language, which is compiled into JavaScript 2 as an intermediary format, and further compiled into either JavaScript 1.5 or ActionScript 3.
Clue and jsc above target multiple runtimes in addition to JavaScript
Illumination [Commercial] Visual, cross-platform tool creates apps for Android, iPhone, iPad, Desktops and HTML5 or Flash websites. The I language underlies the tool.
js.js A JavaScript JavaScript interpreter. Instead of trying to create an interpreter from scratch, SpiderMonkey is compiled into LLVM and then emscripten translates the output into JavaScript.
sweet.js Brings hygienic macros to JavaScript. Lets you write extensions to JavaScript that must be invoked by the user.
acorn A small, fast, JavaScript-based JavaScript parser
SpiderMonkey Parser API - see also reflect.js above. The AST interface specification is succeeded by the ESTree specification effort.
ESTree Specification - An effort to better standardize an AST specification based on the original Spidermonkey Parser API. It is used by Acorn, Esprima, and SpiderMonkey's own parser. This succeeds the original SpiderMonkey Parser API's AST specification.