bellbind/index.html

## index.html
<!doctype html>
<html>
  <head>
    <script type="module">
      document.querySelector("#run").addEventListener("click", async ev => {
        const modUrl = new URL("./module.js", location.href).href;
        //console.log(modUrl);
        const iframe = document.createElement("iframe");
        iframe.style.display = "none";
        document.body.append(iframe);
        const win = await iframe.contentWindow.eval(
          `import("${modUrl}").then(mod => Object.assign(globalThis, mod));`);
        console.assert(win === iframe.contentWindow, "win === iframe window");
        alert(iframe.contentWindow.add(1, 2)); // example
        iframe.remove();
      });
    </script>
  </head>
  <body>
    <button id="run">run es modules in iframe context</button>
  </body>
</html>

## module.js
// es module example with top level await
export const add = await ((a, b) => a + b);
	<!doctype html>
	<html>
	<head>
	<script type="module">
	document.querySelector("#run").addEventListener("click", async ev => {
	const modUrl = new URL("./module.js", location.href).href;
	//console.log(modUrl);
	const iframe = document.createElement("iframe");
	iframe.style.display = "none";
	document.body.append(iframe);
	const win = await iframe.contentWindow.eval(
	`import("${modUrl}").then(mod => Object.assign(globalThis, mod));`);
	console.assert(win === iframe.contentWindow, "win === iframe window");
	alert(iframe.contentWindow.add(1, 2)); // example
	iframe.remove();
	});
	</script>
	</head>
	<body>
	<button id="run">run es modules in iframe context</button>
	</body>
	</html>
	// es module example with top level await
	export const add = await ((a, b) => a + b);