document.addEventListener("DOMContentLoaded", () => { const fullscreenBtn = document.getElementById("fullscreen-btn"); fullscreenBtn.addEventListener("click", () => { try { if (!document.fullscreenElement) { document.documentElement.requestFullscreen(); } else { if (document.exitFullscreen) { document.exitFullscreen(); } } } catch (e) { errorSystem.show('全屏切换失败: ' + e.message); } }); });