I need to exchange messages with the popup, opened by code, via MessageChannel. I open the popup window with window.open() and by default window is blocked, so the result is null. I need to check when user enables the window. Popup window is on another domain. I tried something like this:

const popup = window.open( popupUrl, "Popup", popupWindowFeatures )
const interval = setInterval(() => {
  if (popup) {
    console.log('Popup is opened')
  }
});

But popup is still null, so i cannot post a message to it.

How can I resolve the problem, without manual opening by click or page refresh?