function update_undetected_time() {
  var startdate = new Date($("input#event-start-input-date").val());
  var starttime = timeToDate($("input#event-start-input-time").val());
  var enddate = new Date($("input#event-detect-input-date").val());
  var endtime = timeToDate($("input#event-detect-input-time").val());