How to set focus on an iframe that is cross-domain

Question

Similar to the posts below:

1. Set focus on iframe in Chrome

2. Setting focus to iframe contents

From the root/parent I want to be able to pass focus to the iframe.

Anything that may be in focus in the iframe is fine.

iframe.contentWindow.focus();

However, the iframe.contentWindow is not accessible because its a cross-origin frame.

Answer 1

Seems like the answer is: not possible.

If there is a script running in the iframe you can directly call focus from there.