How to scroll to an iframe with reference to another url?

Question

I have an iframe that has src directed to another url, I know that in this case I can not access the content for security reasons, but what I wanted is to simply position the scroll I a certain position

That is not possible?

I tried to:

$(".scroll").click(function () {
    var iframe = $('#xframe').contents();
    iframe.scrollTop(400);
});

Above the browser locks for security

Also:

$(".scroll").click(function () {
    var iframe = $('#xframe');
    iframe.scrollTop(400);
});

The second has no effect