Embedded JavaScript Events Not running. I need your help.

[caomenglong]

Excuse me

I wrote the following code

first step

/demo.php

code:

<script>
window.addEventListener("message", function(event) {
 console.log(JSON.parse(event.data));
});
</script>

<iframe
  id="looker"
  src="https://instance_name.looker.com/embed/dashboards/1?embed_domain=http://localhost:8010">
</iframe>

Second step
Looker control : Admin -> Embed -> Whitelisting the Embed Domain :
http://localhost:8010 add it, update.

third step
http://localhost:8010/demo.php running,

Look can be displayed normally in the web page.

But EventListener does not work properly, and no message is received.

what am I doing wrong? Please tell me, thank you very much.