full screen class

extend.js

fullScreenClass() {
  const w = window.innerWidth
      || document.documentElement.clientWidth
      || document.body.clientWidth;

  const h = window.innerHeight
      || document.documentElement.clientHeight
      || document.body.clientHeight;

  const ratio = +(h / w);
  const ua = navigator.userAgent;

  // exceed the screen ratio of 16:9
  if (ratio > 1.7777) {
      if (/android/i.test(ua)) {
          return 'android-fullscreen'
      } else if (/iphone/i.test(ua)) {
          return 'ios-fullscreen'
      } else {
          return 'fullscreen'
      }
  } else {
      return '';
  }
}