无法读取属性

Question

这是我的脚本：

            if(entfernung2<=1 && drive=="AUT"){
                dauer = new google.maps.DistanceMatrixService();
                dauer.getDistanceMatrix({
                origins: ["48.142362,11.549859"],
                destinations: ["48.2,11.4"],
                travelMode: google.maps.TravelMode.WALKING,
                unitSystem: google.maps.UnitSystem.METRIC,
                })
            dauer1=dauer.rows.elements.duration.text;
            };

如果我记录 dauer1 会显示以下错误：

未捕获的类型错误：无法读取未定义的属性“元素” 未捕获的类型错误：无法读取未定义的属性“应用”

怎么了？ ：/

编辑：

            if(entfernung2<=1 && drive=="AUT"){
                dauer = new google.maps.DistanceMatrixService();
            dauer.getDistanceMatrix(
            {
              origins: ["48.142362,11.549859"],
              destinations: ['"'+data.position.latitude+','+data.position.longitude+'"'],
              travelMode: google.maps.TravelMode.WALKING,
              unitSystem: google.maps.UnitSystem.METRIC
            }, setDauer1);

            function setDauer1(response, status) {
              dauer1 = response.rows[0].elements[0].duration.value;
              console.log(dauer1);
            }};

Answer 1

getDistanceMatrix 是异步的，所以dauer1 是在dauer 更新之前定义的。通过查看docs，需要回调：

dauer.getDistanceMatrix(
{
  origins: ["48.142362,11.549859"],
  destinations: ["48.2,11.4"],
  travelMode: google.maps.TravelMode.WALKING,
  unitSystem: google.maps.UnitSystem.METRIC
}, setDauer1);

function setDauer1(response, status) {
  dauer1 = response.rows[0].elements[0].duration.text;
  // your code continues here
}