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