<html>
<head><title>Page</title></head>
<body>
<h1>post message test page</h1>
</body>
<script>
let numMessages = 0;
window.addEventListener('message', e => {
numMessages++;
document.title = `postMessage: ${numMessages}`;
e.ports[0].postMessage(`message: ${e.data}, source: ${e.origin}`);
if (e.data.includes('delayed')) {
setTimeout(() => e.ports[0].postMessage(`message: ${e.data}2, source: ${e.origin}`), 1000);
setTimeout(() => e.ports[0].postMessage(`message: ${e.data}3, source: ${e.origin}`), 2000);
}
});
</script>
</html>
