function showAdvancedSearch() {
  document.getElementsByClassName('advanced_search_only').each(function (el) {
    Element.show(el);
  });
  document.getElementsByClassName('simple_search_only').each(function (el) {
    Element.hide(el);
  });
}

function hideAdvancedSearch() {
  document.getElementsByClassName('advanced_search_only').each(function (el) {
    Element.hide(el);
  });
  document.getElementsByClassName('simple_search_only').each(function (el) {
    Element.show(el);
  });
}