function flag_menu_click(sender) {
  $$('img.flag').each(function(image) {
    $(image).src = '/images/flags/inactive/'+image.identify()+'.png';
  })
  $$('.address').each(function(address) {
    address.hide();
  })
  image = $(sender).firstDescendant();
  image_name = image.identify();
  image.src = '/images/flags/active/'+image_name+'.png';
  if (image_name == 'usa') {
    $('wco-logo').src = '/images/wco-logos/us.png';
    $('tta-us').show();
  }
  if ((image_name == 'germany') || (image_name == 'austria') || (image_name == 'switzerland')) {
    $('wco-logo').src = '/images/wco-logos/de_at_ch.png';
    $('tta-de-at-ch').show();
  }
  if ((image_name == 'australia') || (image_name == 'newzealand')) {
    $('wco-logo').src = '/images/wco-logos/au_nz.png';
    $('tta-au-nz').show();
  }
}