1.全屏

// 全屏
    requestFullScreen(element) {
    let de = element || document.documentElement;
    if (de.requestFullscreen) {
        de.requestFullscreen();
    } else if (de.mozRequestFullScreen) {
        de.mozRequestFullScreen();
    } else if (de.webkitRequestFullScreen) {
        de.webkitRequestFullScreen();
    }
    else if(de.msRequestFullscreen) {
      elem.msRequestFullscreen();
    }
  },