function ps(id) {


 if (document.getElementById('dva'+id).style.visibility=='visible')
 {
  document.getElementById('dva'+id).style.visibility='hidden';
  document.getElementById('dva'+id).style.display='none';
 }
 else
 {
  document.getElementById('dva'+id).style.visibility='visible';
  document.getElementById('dva'+id).style.display='block';
 }

}