inject onclick method in the embed iframe

[ronlinet]

Has anybody managed to implement a JS onclick method in the embed iframe?
I have tried

$embed->setAttribute( ["onclick" => 'myMethod( ' . $video['id'] . ' )']);
and

$embed->setAttribute( ["onclick" => 'alert()']);
I see that in web inspector that the events are correctly injected to iframe html tags but I can't trigger even a simple alert.

I my case I want to add a listener for the player button ....