var connNo = 0;
var sum = 0;
var ports = [];
var portNo = 0;
onconnect = function(e) {
  connNo += 1;
    var port = e.ports[0];
    ports[portNo] = port;
    portNo++;
    for(i=0; i<portNo; i++)
    ports[i].postMessage('Connection #' + connNo);
  //port.postMessage('Connection #' + connNo);
  port.onmessage = function(e) {
        sum += parseInt(e.data);
        for(i=0;i<portNo;i++){
            ports[i].postMessage(sum);
        }
  }
}