List of Languages that Compile to JS

It might also be worth looking into Common Node (https://github.com/olegp/common-node) that I'm working on which provides a higher level abstraction: https://gist.github.com/1447709

We wanted to create a cross platform development that could target iOS, Android and other mobile platforms. We started the project about 2 years ago, and saw a few key developments in the JavaScript space.

1. HTML5: the extensions did a lot to move it from a web scripting language to something that could be used for real applications. The Cache Manifest allowed the developer to specify a list of files to be stored on the device, so the app could run offline, with no access to a server.

2. Home Screen: The mobile platforms added the ability to pin web apps to the Home screen with their own icon, making it possible to start them much like native apps.

3. Performance: Work by the browser folks on the internals of the JavaScript engine resulted in huge boosts in performance. The results are in this table: http://www.nsbasic.com/speedtest.htm. You can see the transition from early BlackBerrys being able to run a few hundred JS loops per second to the Motorola Xoom at 718,000. The benchmark is simplistic, but the message is clear: JavaScript on mobile device is 1000 times faster than a few years ago.

It turned out that it was fairly straight forward to write the Translator. Yes, there were enough weird edge cases to question anyone's sanity to do this again, but the result works well. All the control structures translated one to one, so there was little or no drop in performance.

We then built a Visual Studio style IDE around it, with support for frameworks like jQuery Mobile, jqWidgets and Sencha to build a complete dev environment. It's been a lot of fun.

(and yes, you can use JavaScript instead of BASIC if you want!)

It's worth wondering why this is, and I don't really have an answer. In JS's infancy, Java was meant to be the Language of the Web and JS was its asthmatic younger brother. There are probably purely aesthetic problems which led to Java being overtaken by Flash, but I don't know. I sometimes like to say that Java looked consistent in every browser -- but consistently ugly. But Java is not necessarily fun to develop in either, and getting people to install Java always seemed like it was more pain than getting them to install the Flash plugin.

You can treat it as a black box, of course: even to this day, for lots of people, Java on the web just plain doesn't work. But I think you're asking why it doesn't work, and that's much more subtle. You know who would be an interesting person to ask? An advertiser. You see flash ads, you see JS ads, you see flat image ads -- but you never see Java ads.

In any case, I think JS won because it gave immediate gratification: you took the image that you had already placed on the page and, onmouseover, you replaced it with an animated GIF which you'd already loaded and cached. It was event-driven design with a GUI language that you already needed to know when you were making a web app in the first place -- you didn't have to learn AWT and Swing and such before you could make and place a drop-down menu; you just placed a SELECT with OPTIONs, the same as for a form.

When CSS replaced FONT tags and ECMA partly solved the problem of Microsoft trying to kill Javascript in favor of JScript, it became clear to me that JS was indeed the Language of the Web, and that HTML and CSS were just very smart declarative domain-specific languages for its GUIs. If you want a single lesson, there it is: make sure your language allows for declarative programming, and make sure your GUI language is declarative and event-driven.

Its other strengths would not necessarily have been strengths elsewhere. It's an asynchronous language with no race conditions. That's perfect for a responsive GUI, but it's probably wrong for anything which needs lots of processing power. It's got light objects and first-class functions, which is beautiful when you want to package data and write jQuery, but the cool stuff you can do with the Haskell type checker is pretty much not allowed by this model.

But those are the reasons why you might still prefer JS, even when other middle languages exist.

The only other way I can think of is baking it up with the browser. Like Google is doing with Dart. But even they are making Dart compile to JavaScript to make sure you don't lose compatibility between different browsers who opt to not cook Dart in. I remember an interview with one of the Dart developers where he said that having it as a requirement that Dart compiles to JS was greatly limiting the potential of what they can do with Dart. But they can't opt out of it, because compatibility with other browsers is too important.

In short, they're using JS as a middle language because there's no other way to do it. JS is a terrible language, but because of how the web historically developed, we're forced to use it.

A lot of people, myself included, would rather not do any Javascript at all. Particularly those of us who dealt with it early on, since the 90s. It's a pain, a moving target of practices, compatibility and libraries, and quite simply, we hate it. There is massive demand for anything that successfully abstracts as much JS as possible out of the picture. Libraries like Jquery, Prototype, Mootools, ... and whole substitutive systems like Coffeescript, Clojurescript and those others listed.

Happens to Java too. These languages are intensely disliked by many people who have to deal with them because they are infrastructural in their environments. Their architecture is often forced on people who'd much rather program in something else.

Do you expect that any of your additions will get merged into mainline Coco/CoffeeScript?

    [..]
    Family (share genes with CoffeeScript)[citation required]

I'm not trying to be funny or sarcastic, so don't downvote me! That's what Wikipedia is, for better or for worse.