how to parse and return the google direction service response?

Question

how can i parse the response from google direction services ? I am calling javascript code from my iOS WebView, i want to return some value from java script to iOS. I can see the response when i use alert function to display, but it not returning value. I think this is may be the function is callback function. So what should i do ? please tell me the solution

This is my code:

    var value = function() {

var directionsService = new google.maps.DirectionsService();
var directionsDisplay = new google.maps.DirectionsRenderer();
   // var response=new google.maps.DirectionsResult;

var map = new google.maps.Map(document.getElementById('map'), {
                              zoom:7,
                              mapTypeId: google.maps.MapTypeId.ROADMAP
                              });

directionsDisplay.setMap(map);
directionsDisplay.setPanel(document.getElementById('panel'));

var request = {
    origin: 'Chicago',
    destination: 'New York',
    travelMode: google.maps.TravelMode.TRANSIT
};
var temp;
directionsService.route(request,
                        function(response, status)
                        {
                           if (status == google.maps.DirectionsStatus.OK)
                            {
                           t=response.routes[0].copyrights;
                           temp=t;
                           alert(t);
                            directionsDisplay.setDirections(response);
                                  return t;

                            }
                        } );

     return temp;

};

Answer 1

Instead of using the returnValue of value() as a variable inside another function you must call the other function inside the callback of directionsService.route() and pass t as argument to the other function.

Requesting the directionsService is an asynchronous process, it isn't finished yet when value() returns temp, that's why temp still will be undefined.