function toggleLayer( whichLayer )
{
  var elem, vis;
  if( document.getElementById ) // this is the way the standards work
    elem = document.getElementById( whichLayer );
  else if( document.all ) // this is the way old msie versions work
      elem = document.all[whichLayer];
  else if( document.layers ) // this is the way nn4 works
    elem = document.layers[whichLayer];
  vis = elem.style;
  // if the style.display value is blank we try to figure it out here
  if(vis.display==''&&elem.offsetWidth!=undefined&&elem.offsetHeight!=undefined)
    vis.display = (elem.offsetWidth!=0&&elem.offsetHeight!=0)?'block':'none';
  vis.display = (vis.display==''||vis.display=='block')?'none':'block';
}

 function unhide(divID) {
 var item = document.getElementById(divID);
 if (item) {
   if(item.className=='hidden'){
     item.className= 'unhidden';
     document.getElementById(divID + '_filter').style.backgroundImage = "url(/images/toggle-minus.png)";
   
   } else {
      item.className= 'hidden';
     document.getElementById(divID + '_filter').style.backgroundImage = "url(/images/toggle-plus.png)";
     
   }
   
  }
 }