Javascript 如何检查字段是否已动态填充？

我用谷歌地图做了一个计算器，显示出发地和目的地之间的固定价格

但价格只有在离开输入并单击地图或div后才会显示

    $(document).ready(function(){

  function initMap() {
    var latlng = new google.maps.LatLng(52.379189, 4.899431);
    var mapOptions = {
      center: latlng,
      zoom: 11,
      mapTypeControl: false,
      streetViewControl: false,
      styles: [{"featureType":"water","stylers":[{"saturation":43},{"lightness":-11},{"hue":"#0088ff"}]},{"featureType":"road","elementType":"geometry.fill","stylers":[{"hue":"#ff0000"},{"saturation":-100},{"lightness":99}]},{"featureType":"road","elementType":"geometry.stroke","stylers":[{"color":"#808080"},{"lightness":54}]},{"featureType":"landscape.man_made","elementType":"geometry.fill","stylers":[{"color":"#ece2d9"}]},{"featureType":"poi.park","elementType":"geometry.fill","stylers":[{"color":"#ccdca1"}]},{"featureType":"road","elementType":"labels.text.fill","stylers":[{"color":"#767676"}]},{"featureType":"road","elementType":"labels.text.stroke","stylers":[{"color":"#ffffff"}]},{"featureType":"poi","stylers":[{"visibility":"off"}]},{"featureType":"landscape.natural","elementType":"geometry.fill","stylers":[{"visibility":"on"},{"color":"#b8cb93"}]},{"featureType":"poi.park","stylers":[{"visibility":"on"}]},{"featureType":"poi.sports_complex","stylers":[{"visibility":"on"}]},{"featureType":"poi.medical","stylers":[{"visibility":"on"}]},{"featureType":"poi.business","stylers":[{"visibility":"simplified"}]}]
        };
      map = new google.maps.Map(document.getElementById('map'), mapOptions);
  }

  function drivingRoute(from, to) {
    var request = {
      origin: from,
      destination: to,
      travelMode: google.maps.DirectionsTravelMode.DRIVING,
      unitSystem: google.maps.UnitSystem.METRIC
    };
    if(typeof(drivingLine) !== 'undefined') drivingLine.setMap(null);
    directionsService.route(request, function(response, status){
      if(status == google.maps.DirectionsStatus.OK){

        var totalKM = Math.round(response.routes[0].legs[0].distance.value / 1000);
        var distanceText = totalKM+' km';
        $('#controls p').text(distanceText);

        var stadsdeelTest = document.getElementById('stadsdeel').value;
        if (stadsdeelTest=='Centrum') {
                    var charges=  '€ '+ 32;
            }
        else if (stadsdeelTest=='Amsterdam-Oost') {
                    var charges=  '€ '+ 35;
            }
        else if (stadsdeelTest=='Oud-Zuid') {
                    var charges=  '€ '+ 30;
            }

        $('#controls h2').text(charges);

        drivingLine = new google.maps.Polyline({
          path: response.routes[0].overview_path,
          strokeColor: "#b00",
          strokeOpacity: .75,
          strokeWeight: 5
        });
        drivingLine.setMap(map);
        map.fitBounds(response.routes[0].bounds);

      }

      else {
        $('#controls p').addClass('error');
      }

    });

  }

  $('input').blur(function(){
    drivingRoute(
      $('input[name=from]').val(),
      $('input[name=to]').val()
    );
  });

  $(function(){
        $("#geocomplete").geocomplete({
          details: "form",
          types: ["address"],
          country: 'nl'
        });

        $('input').blur(function(){
          $("#geocomplete").trigger("geocode");
        });
      });


  var map;
  var drivingLine;
  var directionsService = new google.maps.DirectionsService();
  initMap();
  $('input[name=to]').val('Schiphol');
  $('input[name=from]').trigger('blur');
});

// Autocomplete
      var fromText = document.getElementById('geocomplete');
      var cityBounds = new google.maps.LatLngBounds(
      new google.maps.LatLng(52.379189, 4.899431));
      var options = {
          bounds: cityBounds,             
          types: ['geocode'],
          componentRestrictions: {country: 'nl'}
      };

  // google.maps.event.addListener(autocomplete, 'place_changed', function() {
  //    window.alert("you selected an item from suggestion list");
  //  });

  $( "input" ).change(function() {
  document.getElementById("bestemming").focus();
            return false;
});

document.getElementById('geocomplete').onkeypress = function (e) {
        if (e.which === 13) {
            document.getElementById("bestemming").focus();
            return false;
        }
    };

例如：

试着把“Damrak，阿姆斯特丹，荷兰”放在出发区，然后点击地图。它显示了次定位中心的价格

将目的地改为“Ceintuurban，Amsterdam，Nederland”后，价格不会改变，只是在点击地图后

---

我想在填写目的地后立即显示价格，如果用户更改了目的地。价格必须自动更改。

不要使用get

blur

事件，请在

输入上尝试
change
事件

  //This is what you have
   $('input').blur(function(){
    drivingRoute(
       $('input[name=from]').val(),
       $('input[name=to]').val()
    );
  });


   //Remove/modify the code above and try this
    $('#geocomplete').bind('input', function() { 
        drivingRoute(
          $('input[name=from]').val(),
          $('input[name=to]').val()
        );
    });

不完全确定这是否回答了您的问题。
我尝试了这两个地方，然后单击了“自动完成”下拉项，它成功了。地图和价格都会自动更新。我不必点击地图来改变它。你是说你想在用户不从下拉列表中选择地点的情况下更新它吗？@搜索你能在不从建议/下拉列表中选择的情况下尝试吗？如果您不从下拉列表中选择，它不会更新价格。不，它不起作用，首先它会显示else价格，单击地图后，它会显示正确子定位的正确价格。。。