Event.observe(window, 'load', function() {
  $$('.see_more').each(function(element) {
    element.observe('click', open_see_more);
  });
});

function open_see_more(event) {
  var element = event.element();
  element.hide();
  element.adjacent("div.see_more_content").each(function(content_element) {
    content_element.show();
  });
  Event.stop(event);
}