Document: fullscreenerror イベント

addEventListener("fullscreenerror", (event) => {});
onfullscreenerror = (event) => {};

const requestor = document.querySelector("div");
function handleError(event) {
  console.error("全画面モードへの移行時にエラーが発生しました");
  console.log(event);
}
document.addEventListener("fullscreenerror", handleError);
// or
document.onfullscreenerror = handleError;
requestor.requestFullscreen();