You know what language I wish could compile to Javascript? Visage (https://code.google.com/p/visage/), AKA JavaFX Script, AKA F3. Now that would be a killer client-side web language.
I'd never heard of Visage. Seems it's a declarative UI language. That raises two questions: what UIs have been built with it, and how does it accommodate the arbitrary code (i.e. imperative rather than declarative) that one inevitably needs as applications become complex?
Ok, three questions: why do you say it would be a killer client-side web language?
The declarative part of Visage/JavaFX Script is simply a clever object instantiation syntax, with its killer feature being the "bind" form. Other than that, Visage is basically statically-typed typed javascript.
It would be great because it's:
1) Looks very familiar to javascript developers
2) Accommodates both the declarative (HTML) and imperative (js) parts of the applications consistently, beautifully and in one place, and ties them together very naturally.
Ok, three questions: why do you say it would be a killer client-side web language?