我是JavaScript新手。我需要获取选中行的值$ {prdcts.precioUnidad}。想法是以动态方式设置总价，因此当用户选中或取消选中每行时，total的值要么在选中时添加新值，要么在未选中时减去前一个值。
我试图使用getElement（）方法获取值，但我不知道如何访问该特定行中变量的值。
这是HTML：
<html><head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Ventas</title>
</head>
<body>
<center><h1>Venta de Productos</h1>
<form action="venta.htm" method="post">
<table id="tableID" border="4">
<tbody><tr>
<th>ID</th>
<th>Nombre</th>
<th>Valor</th>
<th>Comprado</th>
</tr>
<tr>
<td>2</td>
<td>Chupetin</td>
<td>5.0</td>
<td><input name="check" type="checkbox" value="2" label="2" path="prdcts"></td>
</tr>
<tr>
<td>3</td>
<td>Alfajor DDL</td>
<td>30.0</td>
<td><input name="check" type="checkbox" value="3" label="3" path="prdcts"></td>
</tr>
<tr>
<td>4</td>
<td>Sanguche Mila</td>
<td>60.0</td>
<td><input name="check" type="checkbox" value="4" label="4" path="prdcts"></td>
</tr>
</tbody></table>
<br>
<br>
<br>
<table border="4">
<tbody><tr>
<td>Total Compra: <input name="total" id="total" type="number" readonly="" value="0"></td>
</tr>
<tr>
<td>Monto Pagado: <input name="monto" id="monto" type="number" value="0"></td>
</tr>
<tr>
<td>Vuelto: <input name="vuelto" id="vuelto" type="number" readonly="" value="0"></td>
</tr>
<tr>
<td><input name="begin" onclick="calcularVuelto()" type="button" value="Calcular Vuelto"></td>
</tr>
</tbody></table>
<br>
<br>
<input name="clear" onclick="window.location.href = 'venta.htm'" type="button" value="Borrar venta">
<input name="begin" onclick="window.location.href = 'principal.htm'" type="button" value="Inicio">
<input name="confirm" type="submit" value="Confirmar Venta">
<br>
</form>
</center>
<script>
// Make it an Array with "Array.from" so we can use reduce() on it
var $$checkboxes = Array.from(document.querySelectorAll('input[name=check]')),
$total = document.getElementById('total');
// For each checkbox
$$checkboxes.forEach(function ($checkbox) {
// When its value changes, update total
$checkbox.addEventListener('change', updateTotal);
});
function updateTotal() {
// For each checkbox
alert("aca");
var total = $$checkboxes.reduce(function (sum, $checkbox) {
// If it's checked
alert("aca2")
if ($checkbox.checked) {
var price = $checkbox.parentNode.parentNode // parent <tr>
.querySelectorAll('td')[2].innerText.trim(); // remove spaces
// Add price to the sum
return sum + parseFloat(price);
} else {
// If it's not checked, just return the current sum
return sum;
}
}, 0);
$total.value = total.toFixed(2); // Always 2 decimals
}
function calcularVuelto() {
var total = document.getElementById("total").value;
var pago = document.getElementById("monto").value;
var fTotal = parseFloat(total);
var fPago = parseFloat(pago);
totalResta = fPago - fTotal;
document.getElementById("vuelto").value = totalResta;
}
</script>
</body></html>