function referenceMap_onclick(){
		var referenceImg = document.getElementById("img_reference");
		if (referenceImg == null) return;
		
		var ParentHorizontalOffset;
		var ParentVerticalOffset;
		var HorizontalOffset;
		var VerticalOffset;

		if( is5up )
		{
			var element = referenceImg;

			ParentHorizontalOffset = element.offsetLeft;
			ParentVerticalOffset = element.offsetTop;
		
			HorizontalOffset = findPosX(element);
			VerticalOffset = findPosY(element);		
		}
		else
		{
			HorizontalOffset = referenceImg.x;
			VerticalOffset = referenceImg.y;
		}		
		
		HorizontalOffset = HorizontalOffset+2;	
		VerticalOffset = VerticalOffset+2;
		
		var imgX=event.clientX + document.body.scrollLeft;
		var imgY=event.clientY + document.body.scrollTop;
		
		imgX = imgX-HorizontalOffset;
		imgY = imgY-VerticalOffset;
		
		zoomReference(imgX, imgY);		
}