I am trying to add additional DOM elements into stackoverflow for a project.

I am doing this with the developer tools (in chrome).

When I edit the html and add for example:

<h1>Got Milk?</h1>

into stackoverflow everything is ok

Then I tried it with an ifame:

<iframe src="https://google.com/" title="Hey I am just learning"></iframe>

this does not work because of the cross domain policy of stackoverflow, do I understand this correct that there is NO WAY to make this work (no I am not working at stackoverflow and don't have access to their servers)

ok but now my main question is: When I try to insert an iframe with the same url like stackoverflow into SO like this:

<iframe src="https://stackoverflow.com/" title="Hey I am just learning"></iframe>

it triggers emmediately the reloading of the website! this only happens on stackoverflow, but not on other websites. Why is this so and how can i prevent this?