var kShadowPadding = 17;
		
		var kDefaultMagnifierSize = 0; // index into the arrays below
		
		var kMagnifierSizes = new Array(0, 200);
		var kMagnifierSizeNames = new Array('Off', 'On');
		
		var kControllerPrefix = 'Magnifier: ';
		

		function MagnifierPosition()
		{			
			this.style.left = Math.round(this.xPosition - 1 - this.size/2) + "px"; // -1 to account for the border
			this.style.top = Math.round(this.yPosition - 1 - this.size/2) + "px";
			
			this.shadow.style.left = Math.round(this.xPosition - this.size/2 - kShadowPadding) + "px";
			this.shadow.style.top = Math.round(this.yPosition - this.size/2 - kShadowPadding) + "px";
			
			var magnifierCenterX = Math.round(this.xPosition * this.xMultiplier - this.size/2);
			var	magnifierCenterY = Math.round(this.yPosition * this.yMultiplier - this.size/2);
				
			this.style.backgroundPosition = -magnifierCenterX + "px " + -magnifierCenterY + "px";
			
		}
		
		function ControllerSizeButtonClick(event)
		{
			if (!event) event = window.event;
			
			var button = event.currentTarget || event.srcElement;
			
			button.parentNode.magnifier.resize(button.magnifierSize);
		}
		
		function MagnifierResize(size)
		{
			this.size = kMagnifierSizes[size];
			
			for (var i=0; i < this.controller.sizeButtons.length; i++)
			{
				if (i == size)
					this.controller.sizeButtons[i].className = "magnifierControllerButtonSelected";
				else
					this.controller.sizeButtons[i].className = "magnifierControllerButton";
			}
			
			if (this.size == 0)
			{
				this.shadow.style.display = "none";
				this.style.display = "none";
			}
			else
			{
				var shadow = this.shadow;
				var shadowSize = this.size + 2 * kShadowPadding;
				
				// MSIE 5.x/6.x must be treated specially in order to make them use the PNG alpha channel
				var shadowImageSrc = "shadow" + size + ".png";
				if (shadow.runtimeStyle)
					shadow.runtimeStyle.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(src='" +
											     shadowImageSrc +
												 "', sizingMethod='scale')";
				else
					shadow.style.backgroundImage = "url(" + shadowImageSrc + ")";
				shadow.style.width = shadowSize + "px";
				shadow.style.height = shadowSize + "px";
				shadow.style.display = "block";
				
				if (this.runtimeStyle) // msie counts the border as being part of the width
					this.size += 2; // must compensate
				
				this.style.width = this.size + "px";
				this.style.height = this.size + "px";
				this.style.display = "block";
				this.position();
			}
		}
		
		function MagnifierMouseDown(event)
		{
			if (!event) event = window.event;
			
			document.body.magnifier = this;
			this.inDrag = true;
			if (event.pageX)
			{
				this.startX = event.pageX;
				this.startY = event.pageY;
			}
			else if (event.clientX)
			{
				this.startX = event.clientX;
				this.startY = event.clientY;
			}
			else
			{
				alert("don't know how to get position out of event");
				return;
			}
			this.savedCursor = this.style.cursor;
			this.style.cursor = "crosshair";
		}
		
		function MagnifierMouseUp()
		{
			if (this.inDrag)
			{
				this.inDrag = false;
				this.style.cursor = this.savedCursor;
				document.body.magnifier = null;
			}
		}
		
		function MagnifierDrag(event)
		{
			if (!event) event = window.event;
			var magnifier = this.magnifier; // we're actually in the body's onmousemove handler
			
			if (magnifier && magnifier.inDrag)
			{
				var eventX;
				var eventY;
				
				if (event.pageX)
				{
					eventX = event.pageX;
					eventY = event.pageY;
				}
				else if (event.clientX)
				{
					eventX = event.clientX;
					eventY = event.clientY;
				}
				else
				{
					return;
				}
				
				magnifier.xPosition += eventX - magnifier.startX;
				magnifier.yPosition += eventY - magnifier.startY;
				
				magnifier.startX = eventX;
				magnifier.startY = eventY;
				
				magnifier.position();
			}
		}
		
		function loadMagnifier(baseID, zoomedURL, zoomedWidth, zoomedHeight)
		{
			// get the zoomed image (load as early as possible)
			var zoomedImage = document.createElement("img");
			zoomedImage.src = zoomedURL;
			
			// get the div's
			var base = document.getElementById(baseID);
			var magnifier = document.createElement("div");
		
			// get the regular image
			var normalImage = null;
			for (var i=0; i < base.childNodes.length; i++)
			{
				if (base.childNodes[i].tagName &&
					base.childNodes[i].tagName.toLowerCase() == "img")
				{
					normalImage = base.childNodes[i];
					break;
				}
			}
			
			if (normalImage == null)
			{
				alert("couldn't find normal image for magnifier " + baseID);
				return;
			}
			
			magnifier.xMultiplier = zoomedWidth/normalImage.width;
			magnifier.yMultiplier = zoomedHeight/normalImage.height;
			
			magnifier.size = kMagnifierSizes[kDefaultMagnifierSize];
			magnifier.xPosition = normalImage.width - magnifier.size/2 - 20;
			magnifier.yPosition = normalImage.height - magnifier.size/2 + 30;
			
			magnifier.id = baseID + "Magnifier";
			magnifier.className = "magnifier";
			
			// styles (only dynamic ones, rest are part of the class)
			magnifier.style.backgroundImage = "url(" + zoomedURL + ")";
			
			// functions
			magnifier.onmousedown = MagnifierMouseDown;
			magnifier.onmouseup = MagnifierMouseUp;
			document.body.onmousemove = MagnifierDrag; // we attach this handler to the body because if the user moves
													   // the mouse fast enough, it'll go outside the boundaries of the
													   // magnifier, and then the magnifier's mousemove handler won't fire

			magnifier.position = MagnifierPosition;
			magnifier.resize = MagnifierResize;
			
			// controller
			var controller = document.createElement("span");
			
			controller.id = baseID + "MagnifierController";
			controller.className = "magnifierController";
			
			var controllerPrefix = document.createElement("span");
			controllerPrefix.innerHTML = kControllerPrefix;

			controllerPrefix.className = "magnifierControllerPrefix";
			controller.appendChild(controllerPrefix);
			
			controller.sizeButtons = new Array(kMagnifierSizes.length);

			

			for (var i=0; i < kMagnifierSizes.length; i++)
			{
				var button = document.createElement("span");
				button.innerHTML = kMagnifierSizeNames[i];
				button.className = "magnifierControllerButton";
				button.onclick = ControllerSizeButtonClick;
				button.magnifierSize = i;
				
				controller.sizeButtons[i] = button;
				controller.appendChild(button);
			}
			
			// shadow
			var shadow = document.createElement("div");
			
			shadow.id = baseID + "MagnifierShadow";
			shadow.className = "magnifierShadow";
			
			// point objects at each other
			magnifier.controller = controller;
			controller.magnifier = magnifier;
			magnifier.shadow = shadow;
			
			// add to document and lay out

			var controllerContainer = document.createElement("div");
			
			controllerContainer.className = "magnifierControllerContainer";

			controllerContainer.appendChild(controller);

			base.insertBefore(controllerContainer, document.getElementById("message"));
			base.appendChild(shadow);
			base.appendChild(magnifier);
			magnifier.resize(kDefaultMagnifierSize); // also positions
			
		}