function showInfoText(id) {
  document.getElementById('image-text-'+id).style.visibility = 'visible';
  document.getElementById('image-text-'+id).style.zIndex = 10000;
}

function hideInfoText(id) {
  document.getElementById('image-text-'+id).style.visibility = 'hidden';
  document.getElementById('image-text-'+id).style.zIndex = -100;
}