function set_popup_content(header, photo) {
  div_display_on('popup_container');
  p = get_element('popup_photo'); 
  p.innerHTML = '<img class="popup_photo" src="'+photo+'"/>'; 
  h = get_element('popup_header'); 
  h.innerHTML = '<h3>'+header+'</h3>'; 
}
function hide_popup() {
  div_display_off('popup_container');
}

function get_element(id) {
  return document.getElementById(id);
}
function div_toggle_display(id) {
  var display = div_get_display(id);
  if (display=="block") {
    div_display_off(id);
  } else {
    div_display_on(id);
  }
  return e;
}
function div_display_on(id) {
  e = get_element(id);
  e.style.display="block";
  return e;
}
function div_display_off(id) {
  e = get_element(id);
  e.style.display="none";
  return e;
}
function div_get_display(id) {
  e = get_element(id);
  return e.style.display;
}
function enewsletter(url) {
  window.open(url, 
              "enewsletter", 
              "width=650, height=450, scrollbars=yes resizeable=yes");
}