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 popupAdobe()
{
	var width = 650;
	var height = 400;
	var top = (screen.height - height) / 2;
	var left = (screen.width - width) / 2;
	var props = "width=" + width + ",height=" + height + ",screenX=" + left + ",screenY=" + top + ",top=" + top + ",left=" + left + ",scrollbars=yes,resizable=yes";
	var popup = window.open("http://get.adobe.com/reader/", "popupAdobe", props);
	popup.focus();
}