The browser is just a client, people. All of the frameworks for the browser are just (supposed to be) abstractions for creating dynamic browser applications. If you need to create server frameworks specifically for working with a client framework that should be a sign to stop and think that something might be wrong.
But I will disagree on the point that the browser is just a client. It can be treated like that, if you want, but you can take advantage of the fact that the client code is serveable from the same server that has access to the app's data. And that's what Synth was designed for.
But you really shouldn't.
Consider that on projects where the domain problem is simple yet the user requirements are complex, it may make more sense to optimize speed of development of the client.
a webmail client would be a great example of this. The server side is really a small problem, excepting for performance. However, getting the client right is why people still use gmail.