JavaScript - 需要总输入中所有行的总价格总和，但它将这些值连接在一起而不是相加

Question

我想将所有行的总价格相加。但它不能添加值，它只是连接值。这是生成 HTML 的 PHP:

$counter = 0;

foreach($db->getRecordSet($sqlTrRecord) as $row){$counter += 1; ?>
    <tr id="temTr" class="banktblhd">
      <td width="5"> <?php echo($counter); ?> </td>


      <td class="w10"> <input type="number" name="item_code" id="item_code" class="form-control" value="<?php echo($row['item_code']); ?>" readonly  /></td>
      <td class="w10"><input type="text" class="form-control" name="item_name" id="item_name" value="<?php echo($row['item_name']); ?>" readonly /> </td>
      <td class="w10"><input type="text" class="form-control" name="description" id="description" value="<?php echo($row['description']); ?>" readonly /></td>
      <td class="w10"><input type="number" class="form-control" name="availableQty" id="availableQty" value="<?php echo($row['quantity']); ?>" readonly  /></td>
      <td class="w10"><input type="number" class="form-control" name="p_cost" oninput="total(this);" id="p_cost" value="<?php echo($row['p_cost']); ?>" readonly /></td>
      <td class="w10">
        <input type="number" oninput="total(this);" class="form-control" name="quantity" id="quantity" autocomplete="off" /> </td>
      <td class="w10">
        <input type="number" oninput="total(this);" class="form-control" name="sale" id="sale" autocomplete="off" /> </td> 
      <td class="w10"><input type="number" oninput="total(this)" class="form-control" name="total_price" id="total_price" readonly />
      </td>
      <td class="w10" colspan="2"><input type="number" class="form-control"  name="total" id="total" readonly /></td>

这是我的 JavaScript:

function total(element) {
    var row = element.closest("tr");
    var unitRate = row.querySelector("input[name=p_cost]");
    var qty = row.querySelector("input[name=quantity]");
    var sale = row.querySelector("input[name=sale]");

    var total_price = parseFloat(unitRate.value * qty.value) + parseFloat(sale.value);
    var total = row.querySelector("input[name=total_price]").value = total_price;

    document.getElementById("total").value += total;
}

Answer 1

首先，您需要从输入字段获取一个字符串。然后您需要将字符串类型转换为整数，因为默认情况下它被选为字符串

解决方案:parseInt(value)

let num = parseInt(value)

之后num变量可以添加到任意数字类型的变量中。它将开始工作。