升级到iOS 11.3后，web应用程序不会根据支持的apple-mobile-web应用程序显示全屏

<meta name="apple-mobile-web-app-capable" content="yes">

if (navigator.standalone) {
  // Web App is running in standalone mode
} else {
  // Web App is not running in standalone mode
  // Show a button or link to prompt the user to add the app to the home screen
}

var element = document.documentElement;
if (element.requestFullscreen) {
  element.requestFullscreen();
} else if (element.mozRequestFullScreen) {
  element.mozRequestFullScreen();
} else if (element.webkitRequestFullscreen) {
  element.webkitRequestFullscreen();
} else if (element.msRequestFullscreen) {
  element.msRequestFullscreen();
}