function sitemap(id, bool) {
  var self = getElt('self_'+id);
  var childNode = getElt('child_'+id);
  
  if(bool) {
    setEltDisplay(childNode,'block');
    self.innerHTML = '-';
  } else {
    setEltDisplay(childNode,'none');
    self.innerHTML = '+';
  }
  
  self.onclick = function() {
    sitemap(id, !bool);
  }
}