google maps api 3 - Javascript Pass Parameter to Callback or Set Variable Value in DistanceMatrixStatus

Question

I have been playing a little bit with Google's DistanceMatrixService. The code below works, but, how can I pass another parameter to the callback function or grab one of the values out of the callback?

For example: I have two divs that I want to show different results in (Results1 and Results2), so I am thinking I need to either
pass another value to the GoogleMapDistance function like GoogleMapDistance(YourLatLong,DestLatLong,TheDiv)
or
be able to grab the ResultStr externally outside of the callback document.getElementById("Results1").innerHTML = ResultStr;
or
set the innerHTM to the returned value of the function document.getElementById("Results1").innerHTML = GoogleMapDistance(YourLatLong,DestLatLong);

I'm stuck. How can I do accomplish this? The way it looks right now is that I am only going to be able to run all this code once and have it only write to one div.

<div id="Results1"></div>
<div id="Results2"></div>

<script src="https://maps.googleapis.com/maps/api/js?v=3.exp&sensor=false"></script>
<script>

function GoogleMapDistance(YourLatLong,DestLatLong)
{
    var service = new google.maps.DistanceMatrixService();
    service.getDistanceMatrix(
    {
    origins: [YourLatLong],
    destinations: [DestLatLong],
    travelMode: google.maps.TravelMode.DRIVING,
    unitSystem: google.maps.UnitSystem.IMPERIAL,
    avoidHighways: false,
    avoidTolls: false
    }, callback);
}

function callback(response, status)
{
    if (status == google.maps.DistanceMatrixStatus.OK)
    {
    var origins = response.originAddresses;
    var destinations = response.destinationAddresses;
      for (var i = 0; i < origins.length; i++)
      {
          var results = response.rows[i].elements;
          for (var j = 0; j < results.length; j++)
          {
              var element = results[j];
              var from = origins[i];
              var to = destinations[j];
              var distance = element.distance.text;
              var duration = element.duration.text;
              var ResultStr = distance + "&nbsp; (<i>" + duration + "</i>)";
          }
      }
    document.getElementById("Results1").innerHTML = ResultStr;
    }
}

var YourLatLong = "45.4049,-122.797997";
var DestLatLong1 = "47.468893,-122.227978";
var DestLatLong2 = "61.221274,-149.831545";

GoogleMapDistance(YourLatLong,DestLatLong1);

</script>

Answer 1

You can't change how Google calls the callback, but you can let it call your own locally function as the callback and then have that (via a closure) call another callback after adding the desired extra argument like this:

function GoogleMapDistance(YourLatLong,DestLatLong, item)
{
    var service = new google.maps.DistanceMatrixService();
    service.getDistanceMatrix(
    {
    origins: [YourLatLong],
    destinations: [DestLatLong],
    travelMode: google.maps.TravelMode.DRIVING,
    unitSystem: google.maps.UnitSystem.IMPERIAL,
    avoidHighways: false,
    avoidTolls: false
    }, function(response, status) {callback(response, status, item)});
}

Or, you could just define your callback inline so it has access to the parent function variables directly:

function GoogleMapDistance(YourLatLong,DestLatLong, item)
{
    var service = new google.maps.DistanceMatrixService();
    service.getDistanceMatrix(
    {
    origins: [YourLatLong],
    destinations: [DestLatLong],
    travelMode: google.maps.TravelMode.DRIVING,
    unitSystem: google.maps.UnitSystem.IMPERIAL,
    avoidHighways: false,
    avoidTolls: false
    }, function callback(response, status)
    {
        // you can access the parent scope arguments like item here
        if (status == google.maps.DistanceMatrixStatus.OK)
        {
        var origins = response.originAddresses;
        var destinations = response.destinationAddresses;
          for (var i = 0; i < origins.length; i++)
          {
              var results = response.rows[i].elements;
              for (var j = 0; j < results.length; j++)
              {
                  var element = results[j];
                  var from = origins[i];
                  var to = destinations[j];
                  var distance = element.distance.text;
                  var duration = element.duration.text;
                  var ResultStr = distance + "&nbsp; (<i>" + duration + "</i>)";
              }
          }
        document.getElementById("Results1").innerHTML = ResultStr;
        }
    }

)}