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)?'':'none';
  }
  vis.display = (vis.display==''||vis.display=='block')?'none':'';
}


function enableLayer( 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(vis.display==''&&elem.offsetWidth!=undefined&&elem.offsetHeight!=undefined)
  {
    vis.display = (elem.offsetWidth!=0&&elem.offsetHeight!=0)?'':'none';
  }

	vis.display='';
}


function disableLayer( 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(vis.display==''&&elem.offsetWidth!=undefined&&elem.offsetHeight!=undefined)
  {
    vis.display = (elem.offsetWidth!=0&&elem.offsetHeight!=0)?'':'none';
  }

	vis.display='none';
}



function disableLayerCheck( 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];

	if(elem==null)
	{
		return;
	}

  vis = elem.style;

  if(vis.display==''&&elem.offsetWidth!=undefined&&elem.offsetHeight!=undefined)
  {
    vis.display = (elem.offsetWidth!=0&&elem.offsetHeight!=0)?'':'none';
  }

	vis.display='none';
}