var l = -1;

function change_visibility(numb, type, nf) {
  if (l >= 0  && nf && l != numb) {
    change_visibility(l, false);
  }
  var object = $(type + '_form_div' + (numb ? '_' + numb : ''));
  var par = (object.className == type + '_form');
  object.className = (par ? type + '_form_vs' : type + '_form');
  if (nf) {
    if (type == 'opinion')
      document.forms[type + 'Form'].opinion_text.focus();
    else
    {
      document.forms[type + 'Form' + (numb ? numb : '')].question_text.focus();
      l = (l == numb ? -1 : numb);
    }
  }
}