Cannot preserve state in Scala.js

Question

I am trying to write a simple scala.js application. The problem I now have is that I can't figure out why I fail to save data which I get from the server / user.

To be more concrete, here are code snippets:

<!-- in my html -->
<script>
    example.RoomFrontend().setName("@name");
</script>

---

// in my scala.js src
@JSExport
object RoomFrontend extends js.JSApp {
  var username: Option[String] = None
  @JSExport
  def setName(name: String): Unit = {
    username = Some(name)
    g.console.debug(s"Got user name: $name")
  }

  case object TestUserMessage

  class Render(ctx: dom.CanvasRenderingContext2D) extends Actor {
    override def receive: Receive = {
      case TestUserMessage => g.console.debug(s"user name is $username")
    }
  }

  @JSExport
  def main(): Unit = {
    //... 
    // renderer is akka actorRef 
    dom.window.setInterval(() => render ! TestUserMessage, 50)
  }

So, what happens is the following. I succesfully enter user name, e.g. Blah, I see nice message in the js console saying "Got user name: Blah", but the problem is, each time renderer is called, it says username is None.

I imagine it can be caused by my faulty assigning to a variable in one thread (in js main thread, I don't know is it correct definition), and reading this variable from actor thread... But the same story happends with variables stored in actor itself.

I think I don't understand something basic about how one should use scala.js, for I'm new both to scala and js. Please, can somebody explain this odd behavior?