Get sum of subtotal

tally.js

function tally(selector, tdClass) {
            $(selector).each(function () {
                var total = 0,
                    column = $(this).siblings(selector).andSelf().index(this);
                $(this).parents().prevUntil(':has(' + selector + ')').each(function () {
                    total += parseFloat($('td.'+ tdClass +':eq(' + column + ')', this).html()) || 0;
                })
                $(this).html('<strong>' + total + '</strong>');
            });
        }