JavaScript: Parent -> Frame function calls

For this example I have 2 html pages:

Page1.html and Page2.html

If Page2 is shown as iframe inside Page1 and has this function:

<script type="text/javascript">

        function showMessage(m) {

            document.getElementById("message").innerHTML = m;

        }

</script>

Than it can be called from Page1 like this:

<script type="text/javascript">

    window.onload = function() {

        window.frames[0].showMessage("Hello from Main Page in iFrame");

    };    

</script>

 

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