function begrip(id, bool) {
  var self = getElt('begrip_'+id);
  var childNode = getElt('PagVld_'+id);
  
  if(bool) {
    setEltDisplay(childNode,'block');
  } else {
    setEltDisplay(childNode,'none');
  }
  
  self.onclick = function() {
    begrip(id, !bool);
  }
}