List of languages that compile to JS

CoffeeScript Family (& Friends)

• CoffeeScript Unfancy JavaScript

Family (share genes with CoffeeScript)

• 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.
• Parsec CoffeeScript is 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.

Friends (philosophically related)

• Kaffeine Enhanced Syntax for Javascript.
• Jack Making programming playful.

JavaScript

• Narcissus Experimental javascript compiler in javascript by Brendan Eich and others.
  • CommonJS version in DoctorJS
  • Jasy: Python port of Narcissus with some enhancements
• Closure Compiler An optimizing compiler. Can generate a (line/col)-number mappings file.
• UglifyJS

Security enforcing JavaScript

• Caja Compiles ES5/strict to ES3 and supports object-capabilities
• ADsafe Client-side static verifier and API, making third party scripts safe.
• FBJS Facebook JavaScript, used for scripting FBML (Facebook Markup Language) gadgets.
• Jacaranda Static verifier supporting object-capabilities.
• Microsoft Web Sandbox a technology preview of securing web content through isolation.
• Gatekeeper a Microsoft Research project.
• Dojo Secure a framework for building secure mashups.

Ruby

• HotRuby runs opcode, compiled by YARV on Ruby inside a web browser or in Flash.
• rb2js converts Ruby to JavaScript.
• Red writes like Ruby and runs like JavaScript
• Quby used for game coding site, not open source.

Python

• PYXC-PJ [CS friend] Python to JS. Can generate a (line/col)-number mappings file.
• Pyjamas Python to JS.
• Skulpt Python. Client side.
• PyCow Python to MooTools JS.
• PyvaScript Python-like syntax to JavaScript.

Lisp, Scheme

• Parenscript subset of Common Lisp to JS.
• Sibilant Javascript with a lisp
• Moby Scheme a Scheme running in JS.
• scheme2js Scheme to JavaScript
• ClojureScript translates code written in a very small subset of Clojure.
• clojurejs subset of clojure to JS
• Scriptjure library for generating javascript from Clojure forms.

OCaml

• Ocamljs OCaml to JS
• O'Browser OCaml bytecode interpreter in JS
• Js_of_ocaml OCaml bytecode to JS compiler

Haskell

• UHC (Utrecht Haskell Compiler) backend converts UHC core to JavaScript, allowing the compiling of Haskell code to JS.
• YHC (York Haskell Compiler) backend, as above but with YHC core language.

Multitarget

• Haxe compiles to several platforms (C++, Flash, JS, Neko, PHP).
• Clue C language compiler to different runtimes (Lua, JS, Perl 5, C, Java, CL).
• Fantom Evolutionary Object Oriented language emphasizing succinct and effective APIs (JVM, CLR, JS).

Tierless languages (produce both client & server)

• One Pot Application [free for non commercial] industrial programming language for high-security distributed web applications.
• Fun A programming language for realtime webapps - compiles to client-side and server-side JS
• Ur in the tradition of ML and Haskell.
• WebSharper lets you compile F# to JS
• mobl the new language for programming the mobile web.
• GWT Java to JS.
• E Compiles E to JS. E is a secure distributed persistent pure object language.

Others

• Oia a port of Io to Javascript
• NS Basic/App Studio [commercial] Visual Basic-style BASIC to Javascript compiler. Includes IDE. Targets iOS and Android.
• Emscripten LLVM to Javascript compiler
• 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.
• Clamato a Smalltalk dialect that is designed to operate within the JavaScript runtime.
• Flapjax Event-driven, reactive evaluation.
• StratifiedJS JavaScript + structured concurrency.
• NarrativeJS Javascript extension with asynchronous futures and promises.
• JS2 Object Oriented Javascript with syntactic sugar (curry, foreach, property). Released as a rubygem.
• jsc [experimental] recompile your .net assembly to javascript, actionscript, php or java
• jwacs Javascript With Advanced Continuation Support
• j2js Java Bytecode to JavaScript

Static typed

• Some of the ones listed above are statically typed, such as mobl, GWT, NS Basic, Haxe
• Script# [commercial] compiles C# to JS.
• 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