function show_instances() {
  if(document.getElementById('locations_str') && document.getElementById('locations_str').style) {
    document.getElementById('locations_str').style.display = 'block';
  }
}

function hide_instances() {
  if(document.getElementById('locations_str') && document.getElementById('locations_str').style) {
    document.getElementById('locations_str').style.display = 'none';
  }
}