var pos = 0;
	// initial images (pre-load)
	if (document.images)
		{
			for (i=0; i<imgArray.length; i++)
				{
					eval("imgObj" + i + "= new Image()");
					eval("imgObj" + i + ".src = '" + imgDir + imgArray[i] + "'");
				}
		} 
		
	function toPrevious()
		{
			if (pos == 0) { pos = imgArray.length - 1;}
			else { pos = pos - 1 };
			
			eval("document.vvr.src = imgObj"+pos+".src");
		}

	function toNext()
		{
			if (pos == imgArray.length - 1) { pos = 0; }
			else { pos = pos + 1; }
			
			eval("document.vvr.src = imgObj"+pos+".src");
		}