var openLegendId = "";
			var mapTop = 0;
			var mapLeft = 0;
			var mapHeight = 0;
			var mapWidth = 0;
			
			function ToggleLegendDisplay(divId) {
				//Obtain reference to specified map legend
				var objDiv = document.getElementById(divId);
				//Hide map legend currently showing.
				if (openLegendId != "") {
					hideLegend(openLegendId)  
				}
				//Show specified map legend.
				showLegend(divId)
				//Position legend over map
				objDiv.style.pixelTop = mapTop + Math.floor((mapHeight - objDiv.offsetHeight) / 2)
				objDiv.style.pixelLeft = mapLeft + Math.floor((mapWidth - objDiv.offsetWidth) / 2)
				//Update currently showing legend id.
				openLegendId = divId
			}
			
			function showLegend(divId) {
				document.getElementById(divId).style.display = "block"  
			}
			
			function hideLegend(divId) {
				document.getElementById(divId).style.display = "none"  
			}
			
			function getAscendingTops(elem) {
				var oTop = 0;
				var obj = elem;
				while (obj != null) {
					oTop += obj.offsetTop
					obj = obj.offsetParent
				}
				return oTop
			}

			function getAscendingLefts(elem) {
				var oLeft = 0;
				var obj = elem;
				while (obj != null) {
					oLeft += obj.offsetLeft
					obj = obj.offsetParent
				}
				return oLeft
			}
			
			function getMapCoords(mapId) {
				var objImg = document.getElementById(mapId) 
				mapTop = getAscendingTops(objImg)
				mapLeft = getAscendingLefts(objImg)
				mapHeight = objImg.offsetHeight
				mapWidth = objImg.offsetWidth
			}