var previousLayerId = 'None';

function toggleLayer( whichLayer )
{
  var elem, vis;
  var count = 0;
  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;
  vis.background == 'red';
  // 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)?'':'none';
    previousLayerId = 'None';
    vis.display = (vis.display==''||vis.display=='block')?'none':'';
  }
  else
  {
    if (previousLayerId != 'None')
    {
    	closePreviousLayer(previousLayerId);
    }
    previousLayerId = whichLayer;
    vis.display = (vis.display==''||vis.display=='block')?'none':'';
  }
  

  
}

function closePreviousLayer(whichLayer2)
{

}



function hideLayer( 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;

  vis.display = 'none';
  
}

function showLayer( 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;

  vis.display = '';
}