//http://www.netlobo.com/div_hiding.html
function toggleLayer( whichLayer )
{
  var elem, vis;

  elem = getLayer( whichLayer );

  if( elem )
  {
      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';
  }
}


//http://www.netlobo.com/div_hiding.html
function getLayer( whichLayer )
{
  var elem
  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];

  return elem;
}


function hideLayer( whichLayer )
{
  var elem, vis;

  elem = getLayer( whichLayer );

  if( elem )
  {
      vis = elem.style;
      vis.display = 'none';
  }
}