如何检测纯javascript对全屏api的支持？

function isFullScreenSupported() {
  return (
    document.fullscreenEnabled ||
    document.mozFullScreenEnabled ||
    document.webkitFullscreenEnabled ||
    document.msFullscreenEnabled
  );
}

function requestFullScreen(element) {
  if (element.requestFullscreen) {
    element.requestFullscreen();
  } else if (element.mozRequestFullScreen) {
    element.mozRequestFullScreen();
  } else if (element.webkitRequestFullscreen) {
    element.webkitRequestFullscreen();
  } else if (element.msRequestFullscreen) {
    element.msRequestFullscreen();
  }
}

if (isFullScreenSupported()) {
  // 浏览器支持全屏API
  console.log("浏览器支持全屏API");
  // 进入全屏
  requestFullScreen(document.documentElement);
} else {
  // 浏览器不支持全屏API
  console.log("浏览器不支持全屏API");
}