var timeout = -1;
var started = -7500;
var update_timeout = () => (Date.now() - started > (UPDATE_INTERVAL / 2 + 5000) / 2) ? (clearTimeout(timeout), update(), started = Date.now(), timeout = setTimeout(update_timeout, UPDATE_INTERVAL)) : null;
window.onfocus = () => (Date.now() - updated > (UPDATE_INTERVAL / 2 + 10000) / 2) ? update_timeout() : null;
update_timeout();