Groundsource embed

// Create IE + others compatible event handler; var eventMethod = window.addEventListener ? "addEventListener" : "attachEvent"; var eventer = window[eventMethod]; var messageEvent = eventMethod == "attachEvent" ? "onmessage" : "message"; // Listen to message from child window eventer(messageEvent,function(e) { if( !isNaN(e.data) && parseInt(e.data) > 0 ) { var heightNum = parseInt(e.data); var newHeight = heightNum+50; document.getElementById('gsexternal').height = newHeight + 'px'; } },false);