const state ={height: -1, url: ''};

function urlWithoutOrigin(url){
  return url.replace(new URL(url).origin, "");
}

function sendEvent(){
  const height = document.documentElement.offsetHeight;
  const url = urlWithoutOrigin(document.URL);
  if(height === state.height && url === state.url){
    return;
  }
  state.height = height;
  state.url = url;
  const event = {... state};
  window.parent.postMessage(event, "*");
}

window.setInterval(sendEvent, 100)