Untitled

<!doctype html>
<meta charset="utf-8">
<title></title>
<script>

var outerWorker = new Worker('a.js');
/*
  Code von a.js:
  this.onmessage = function(evt){
    var port = evt.data.port;
    port.onmessage = this.postMessage.bind(this);
    port.postMessage(23);
  };
*/

var innerWorker = new Worker('b.js');
/*
  Code von b.js:
  this.onmessage = function(evt){
    if(evt.data === 23){
      this.postMessage(42);
    }
  };
*/

function createProxy(worker){
  var channel = new MessageChannel();
  var localPort = channel.port1;
  var remotePort = channel.port2;
  localPort.start();
  remotePort.start();
  localPort.onmessage = function(evt){
    worker.postMessage(evt.data);
  };
  worker.onmessage = function(evt){
    localPort.postMessage(evt.data);
  }
  return remotePort;
}
var proxy = createProxy(innerWorker);

outerWorker.postMessage({
  port: proxy
}, [proxy])

innerWorker.onmessage = function(evt){
  window.alert(evt.data); // > 42
};

</script>