Angular has been using its own AtScript superset of Microsoft’s TypeScript for a while now. TypeScript is Microsoft’s attempt at extending JavaScript with features like type annotations, generics and modules. Going forward, the two languages will converge. Angular 2 will be written in TypeScript and developers will be able to write their Angular 2 applications in this language,too."
The Mozilla Project "Shumway" "Shumway is in a race to stay relevant as Flash fades from the web, but there will always be a long-tail of Flash content that would/will be lost when Adobe or browsers stop supporting the Flash plugin."
FAYDE - SILVERLIGHT IN JAVASCRIPT AND HTML5 CANVAS "At the same time, there's The Fayde project. Also Open Source, Fayde also compiles to JavaScript. But Fayde transforms Silverlight into HTML5 Canvas and JavaScript! It's an implementation of a XAML engine in JS."