Why don't you choose JSX or TypeScript? The latter is a superset of JavaScript, so migration should be a breeze. If you'd like the same language for client and

Why don't you choose JSX or TypeScript? The latter is a superset of JavaScript, so migration should be a breeze. If you'd like the same language for client and server side, try Kotlin or HaXe. For now, Dart doesn't have a crossbrowser VM yet (except for Dartium), so it doesn't give you any performance boost over JavaScript. Maybe one day there will be a cross-browser Dart VM as a PNaCl or asm.js module?