function switch_product_img(divName, totalImgs) {
	for (var i=1; i<=totalImgs; i++) {
		var showDivName = 'photo_' + i;
		var showObj = document.getElementById(showDivName);
		if (showDivName == divName)
			showObj.style.display = 'block';
		else
			showObj.style.display = 'none';
		}
}