function listTypeChanged(){
  id = '#'+$('#shoe_width').val().toLowerCase().replace(/\s/gi, "_");
  $('.shoe-size').hide();
  $('.shoe-size select').attr('selectedIndex', 0).removeAttr('required');
  $('div.error').hide();
  if(id.length > 1) {
    $(id).show();
    $(id + ' select').attr('required', 'required');
  }
}

$(document).ready(function(){
  $('#shoe_width')
    .change(function(){listTypeChanged();})
    .each(function(){$(this).attr('required', 'required');});
  listTypeChanged();
});