var ua = window.navigator.userAgent.toLowerCase();
    var isIphoneX = window.screen.height === 812 && /iphone/.test(ua);
    if (isIphoneX) {
      var viewport = document.querySelector("meta[name=viewport]");
      var _content = viewport.getAttribute('content') + ', viewport-fit=cover';
      viewport.setAttribute('content', _content);
    }