const status = document.getElementById("status"); const radios = document.querySelectorAll('input[name="mode"]'); async function request(method, body) { try { const resp = await fetch("/mode", { method, headers: { "Content-Type": "application/json" }, body: body && JSON.stringify(body), }); showMode((await resp.json()).mode); } catch (e) { status.textContent = "Backend error"; } } function showMode(mode) { radios.forEach((r) => (r.checked = r.value === mode)); status.textContent = `Tracking with: ${mode}`; } radios.forEach((r) => r.addEventListener("change", () => request("POST", { mode: r.value })) ); request("GET");