JSFiddle - React, Tailwind, and code Playground

HTML

Product ID: 1065

    <input type="text" class="text cart_qty" id="Form_OrderForm_Product-1065-qty" name="Product[1065][qty]" value="1" />

    <input type="text" class="text prod_id" id="Form_OrderForm_prod_1065" name="prod_1065" value="1000" />

    <input class="hidden" type="hidden" id="Form_OrderForm_hidden_1065" name="hidden_1065" value="1.45" />

    Line total: <span id='Product_1065_Line' class='cart_price_line'>1.45</span>

<hr />

    Product ID: 1337

    <input type="text" class="text cart_qty" id="Form_OrderForm_Product-1337-qty" name="Product[1337][qty]" value="1" />

    <input type="text" class="text prod_id" id="Form_OrderForm_prod_1337" name="prod_1337" value="500" />

    <input class="hidden" type="hidden" id="Form_OrderForm_hidden_1337" name="hidden_1337" value="1.45" />

    Line total: <span id='Product_1337_Line' class='cart_price_line'>1.45</span>

<hr />
Total: <span id="total_price_curr"></span>

JavaScript

$("document").ready(function() {

    $('.cart_qty').keyup(function(){
        var $thetotal=0;

        $('input.cart_qty').each(function(index) {

         $theqty=$(this).val();
         $thenextindex=$("input").index(this) + 2;
         $theprice=$("input:eq("+$thenextindex+")").val();

         $thelinetotal=$theqty * $theprice;
         $thetotal=$thetotal + $thelinetotal;

            var product_id = $(this).attr("id").split("-")[1];
            $("#Product_" + product_id + "_Line").html($thelinetotal);
        });
        $("#total_price_curr").html($thetotal);
        $("#Form_OrderForm_totalHidden").val($thetotal);

    });

});