cross-origin iframe.html

<iframe id="nascar_frame" frameborder="0" height="5700" scrolling="no" src="http://chasehub.azurewebsites.net/"></iframe>

<script type="text/javascript">
	(function ($) {
		$(window).scroll(function() {
			var topPosition = $(window).scrollTop();
			if($('#nascar_frame')) {
				$('#nascar_frame')[0].contentWindow.postMessage('nascar_' + topPosition, 'http://chasehub.azurewebsites.net/');
			}
		});
	})(jQuery);
</script>

<!-- within iframe -->
<script>
  window.addEventListener('message', function(e) {
		var message = e.data.split('_');
		if(message.length) {
			var topPosition = message[1];
			topPosition -= 260;
			$('.popup').css('top', topPosition + 'px');
		}
	});
</script>