JQuery operation/get table specific code_jquery

$("#nav_box tr" ).each(function (i) {
//var text = $(this).children("td:first").text();
//var proid = $(this).find( "input:hidden").val();
//alert("proid==" i "===" proid);
var num = $("#ProNum" i).val() ; //Quantity
var price = $("#Price" i).val(); //Price
var percent = $("#Percent" i).val(); //Discount
var discountAmount = percent * price; //Discount price
$("#discountAmount" i).val(discountAmount.toFixed(2)) //Discount price
var total = discountAmount * num; //Small Total = discount price * quantity
$("#Total" i).val(total.toFixed(2)); //Subtotal
});