function showBlock(obj) {
  var el = document.getElementById(obj);
  el.style.display = 'block';
}

function hideBlock(obj) {
  var el = document.getElementById(obj);
  el.style.display = 'none';
}

function toggleBlock(obj) {
  var el = document.getElementById(obj);
  if ( el.style.display != 'none' ) {
    el.style.display = 'none';
  }
  else {
    el.style.display = 'block';
  }
}