jQuery(document).ready(function() {
var windowHeight = $(window).height();
var headerHeight = $('.page-header').height();
$('iframe#child-page-frame').height(windowHeight - headerHeight).css('margin-top', headerHeight);
$(window).resize(function () {
var windowHeight = $(window).height();
var headerHeight = $('.page-header').height();
$('iframe#child-page-frame').height(windowHeight - headerHeight).css('margin-top', headerHeight);
});
});