监听页面全屏事件

      document.addEventListener('webkitfullscreenchange', () => {
        const isFullScreen = document.fullScreen || document.mozFullScreen || document.webkitIsFullScreen
        if (isFullScreen) {
          //  进入全屏
          console.log('进入全屏')
        } else {
          //  退出全屏
          console.log('退出全屏')
        }
      })