C# MVC has an attempt at creating some validation and automagically promoting that to the UI but it's (of course) limited to stuff like "this field is numeric"

C# MVC has an attempt at creating some validation and automagically promoting that to the UI but it's (of course) limited to stuff like "this field is numeric" or "this field is required". Anything more complex needs duplication. I would assume that something like node.js or meteor have it easier, since they're using the same language in both layers; I believe there are also attempts at tools that automatically translate other languages to JS but I haven't used any of them.