在函数中添加JS变量

Question

大家好，我需要给这个函数的总变量vl加上一个变量值。

id('total-quotas').addEventListener('keyup', function () {
           id('vl_total').value = id('total-quotas').value;
        });

我试着这样做，但没有

id('total-quotas').addEventListener('keyup', function () {
           id('vl_total').value = (id('total-quotas').value + id('valor6').value);
        });

我的另一个函数，例如

id('valor8').addEventListener('keyup', function () {
            var conv = id('valor8').value.replace("R$", "");
            var conv2 = conv.replace("," , ".");
            var totalquotasConv = id('total-quotas').value.replace("R$", "");
            var totalquotasConv2 = totalquotasConv.replace(",", ".");

            var result = parseFloat(conv2) / parseFloat(id('qtd_vezes_parcela').value);
            var result2 = parseFloat(totalquotasConv2) - parseFloat(conv2);
            var resConv = result.toFixed(2).toString();
            var resConv2 = result2.toFixed(2).toString();
            id('valor6').value = resConv.replace(".", ",");  
            id('valor9').value = resConv2.replace(".", ",");
        });

Answer 1

尝试如下所示：

id('total-quotas').addEventListener('keyup', function () {

    const vl_total = id('vl_total');
    const total_quotas = id('total-quotas');

    if (total_quotas.value) {
        vl_total.value = total_quotas.value
            ? parseInt(total_quotas.value, 10) 
            : 0;
    }
});

另一个例子：

id('total-quotas').addEventListener('keyup', function () {

    const vl_total = id('vl_total');
    const total_quotas = id('total-quotas');
    const valor6 = id('valor6');

    if (total_quotas.value && valor6.value) {

        const a = total_quotas.value ? parseInt(total_quotas.value, 10)  : 0;
        const b = valor6.value ? parseInt(valor6.value, 10)  : 0;
        vl_total.value = a + b;
    }
});