var i=0;
var update = null;
function timedCount(){

  onmessage = (e) => {


    if(e.data == "on"){
      console.log("on");
      update = setInterval("stationupdate()", 3000);
    }

    if(e.data == "off"){
      clearInterval(update);
    }
}


}
function stationupdate(){

  postMessage("up");
}

timedCount();