How to change the styles of the iframe itself from the contents of the iframe?

Question

css

Good afternoon, on the 2nd day we can’t solve the problem with the site, the site says from the content change iframe styles so that the banner gets up normally, but we insist on our own that this is impossible, if it were possible, then when the site is sleeping, we would change the size of the banner 100% to 100%, which is not logical.

Example:
there is an iframe there is banner.html content is it possible to change the iframe style tag from the banner.html content?
<iframe src="banner.html" />

<img src="1.jpg" />

Answer 1

You can't do that, you can't change the style of an iframe from the iframe itself.

Answer 2

Alternatively use postMessage
https://developer.mozilla.org/en-US/docs/Web/API/W...