Question

我正在寻求以下帮助...

我有一个费用表，用户可以输入里程索赔和任何其他费用。例如，如果您在0-9英里之间旅行，则可以获得5英镑的固定费用，10-19英里可以获得7英镑，20-20英镑等等。

我有一个小计div，我希望每当里程值改变时更新，但我的计算小计的函数似乎在AJAX调用之前执行以使定价带完成。

小计功能基本上是：

function calculateClaim() {
    var mileageDistance = document.getElementById('journeyMileage').value;
    var expenseAmount1 = document.getElementById('expenseAmount1').value;
    var expenseAmount2 = document.getElementById('expenseAmount2').value;
    var expenseAmount3 = document.getElementById('expenseAmount3').value;
    if (mileageDistance != "") {
        calculateMileage = calculateMileageTotal(mileageDistance, function() {
            var mileageTotal = this;
            if (mileageTotal == '') {
                $("#mileageTotal").val(0.00);
                $("#journeyAmount").html('<strong>&pound;0.00</strong>');
                showDialog('alert','OK','','There is no mileage payment set up.','');
            } else {
                mileageTotal = parseFloat(mileageTotal).toFixed(2);
                $("#mileageTotal").val(mileageTotal);
                $("#journeyAmount").html('<strong>&pound;' + mileageTotal + '</strong>');
            }
        });
    } else {
        mileageTotal = 0;
        mileageTotal = mileageTotal.toFixed(2);
        document.getElementById('journeyAmount').innerHTML = '<strong>&pound;</strong>';
    }
    /* 
        SOME VALIDATION STUFF HERE FOR OTHER EXPENSE FIELDS
    */  
    subTotalCost = parseFloat(mileageTotal) + parseFloat(expenseAmount1) + parseFloat(expenseAmount2) + parseFloat(expenseAmount3);
    subTotalCost = subTotalCost.toFixed(2);
    document.getElementById('subTotal').innerHTML = '<strong>&pound;' + subTotalCost + '</strong>';
}

调用的calculateMileageTotal函数如下：

function calculateMileageTotal(mileage,callback) {
    var mileageDistance = mileage;
    var mileageTariffExists = $('#mileageTariffExists').val();
    if (mileageTariffExists == 1) {
       $.ajax({
            type: "POST",
            url: "./ajaxQueries.cfc?method=getExpensesMileageBand",
            data: ({
            competitionID: $("#compID").val(),          
            matchDate: $("#matchDate").val(),
            mileageTotal: mileageDistance
            }),
            dataType: "xml",
            success: function(xml) {
                $(xml).find('field').each(function(){
                    //alert((new XMLSerializer()).serializeToString(xml));
                    var mileageTotal = $(this).find('string').text();
                    callback.call(mileageTotal);
                });
            }
        });
    } else {
        showDialog('alert','OK','','There is no Mileage Rate available.','');
    }
}

getExpensesMileageBand函数肯定正常运行并返回里程率，但它是认为mileageTotal值为空的子总计算，因为它还没有从函数返回但是如果我在那里放了几个警报工作（因为它减慢了功能）。

有人有任何想法吗？我之前没有使用过回调，所以我不确定这是不是我错了？

Answer 1

为什么不将小计计算作为一个单独的函数，从回调的结尾或else语句的结尾调用。

function calculateSubtotal(milageTotal) {
  subTotalCost = parseFloat(mileageTotal) + parseFloat(expenseAmount1) + parseFloat(expenseAmount2) + parseFloat(expenseAmount3);
  subTotalCost = subTotalCost.toFixed(2);
  document.getElementById('subTotal').innerHTML = '<strong>&pound;' + subTotalCost + '</strong>';
}

if (mileageDistance != "") {
  calculateMileage = calculateMileageTotal(mileageDistance, function() {
    var mileageTotal = this;
    if (mileageTotal == '') {
      // existing code
    } else {
      // existing code
      calculateSubtotal(milageTotal);
    }
  });
} else {
  // existing code
  calculateSubtotal(milageTotal);
}

在回调完成之前完成的Javascript函数

1 个答案: