How to make the function execution when you hover on an object (JS)?

There is such a code https://jsfiddle.net/25q0ex97/3/ . (works out only in new versions of Chrome)

It should work when you hover

document.getElementById('page').onmouseover = function(){ document.getElementById('paste').click(); }; 

The code works fine when loading the local version. But when loading "from the outside" (apparently due to the work of the iframe) for the code to work it is required to "touch" the window - just by clicking.

Ie the usual cursor on the iframe itself does not activate the code.

But at the same time, here is an example of https://jsfiddle.net/richardcwc/qdjkreo5/ where the code is triggered in the iframe, directly by an alert.

I read for promise, maybe this is the case, but with my base I did not find anything there :(

Tell me :( Thank you!