<meta charset=utf-8> <script> "use strict"; window.addEventListener("appinstalled", () => { document .querySelector("#output") .innerHTML = "event received!"; // Send a custom event back to the browser // to acknowledge that we got this const detail = { result: true } const ev = new CustomEvent("dom.manifest.onappinstalled", { detail }); document.dispatchEvent(ev); }); </script> <h1 id=output>waiting for event</h1>