function showhide(vad){
  var o = gObj(vad);
  if(o != null && o.style != null){
  o.style.display = (o.style.display == 'none')? '' : 'none';
  }
}
function gObj(nm){
  if(document.getElementById) return document.getElementById(nm);
  else if(document.layers)  return document.layers[nm];
  else  return document.all[nm];
}