const elementCoordinates = document.querySelector('#bontour_frame').getBoundingClientRect();
Scroll_Top = elementCoordinates.top;
function listener(event) {
if (event.data=='scroll')
$('html, body').animate({scrollTop:Scroll_Top}, 'slow');
else
document.getElementById("bontour_frame").style.height = event.data + "px";
}
if (window.addEventListener) {
window.addEventListener("message", listener, false);
} else {
window.attachEvent("onmessage", listener);
}