// show/hide layers
		
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';
}

//show/hide layers end

// swap images
<!-- 

	if (document.images) {
		map_lightbox = new Image
		map_ambulatory = new Image	
		map_goodisonroom = new Image
		
		map_image1 = new Image

		map_lightbox.src = "images/map_small_1.gif"
		map_ambulatory.src = "images/map_small_2.gif"
		map_goodisonroom.src = "images/map_small_3.gif"
		
		map_image1.src = "images/map_small.gif"
			
		
	}
	
	function chgImg(imgField,newImg) {
		if (document.images) {
			document[imgField].src= eval(newImg + ".src")
		}
	}
		
// End hiding script from old browsers -->
// swap images ends