HTTP Posts with dynamic forms

Is there an idiomatic way to handle HTTP posts with dynamic forms?

Specifically, I have some JQuery code that allows people to add or remove text forms that are meant to contain e-mail addresses, which will then be POSTed to a web server.

I can add an counter to increment the name of each form. Is there a way to tell from the server-side how many text forms there are in total?

Or is there a better way of doing this?

For what it's worth, the web server is Scala with Vertx.