let worker;
function initiate() {
  const button = document.getElementById("button");
  button.addEventListener("click", send);

  worker = new SharedWorker("worker.js");
  worker.port.addEventListener("message", received);
  worker.port.start();
}
function received(event) {
  alert(event.data);
}
function send() {
  const name = document.getElementById("name").value;
  worker.port.postMessage(name);
}
window.addEventListener("DOMContentLoaded", initiate);