How to insert value to external iframe input

Question

I have button and external iframe, and I need click to button to insert to this iframe input some value

$("#button").click(function(){
    $('iframe').find('input').val('value');
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.0.0/jquery.min.js"></script>
<button id='button'>test</button>
<br>
<iframe src="http://www.abc.sk/pridat.aspx" width='900' height='500'></iframe>

EXAMPLE

Answer 1

Main frame and pridat.aspx have to be hosted on the same domain www.abc.sk