child.html
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<body><h2>子页面</h2>
</body>
<script>
window.addEventListener('message', function (event) {
console.log(event);
alert(event.data);
}, false);
</script>
</html>
main.html
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<body>
<iframe id="child" src="./iframepage.html"></iframe>
<script>
window.onload = function () {
document.getElementById('child').contentWindow.postMessage("lllllllllllllllll", "*")
}
</script>
</body>
</html>
