Question

hi i am having the same probem as here Return address from Google Maps Geocoder v3 , i dont understand how to set my global variable to the return vlaue

i got this at the moment where b returns undefined

 var a;
 var b;
function outputGeo(result){
    b = result; 
     }


 geocoder.geocode({'latLng': event.latLng},function(results, status) {

         a =  results[1].formatted_address;
         outputGeo(a);
        });  
alert(b);

Answer 1

geocoder.geocode is an asynchronous function because it’s performing a JSONP request. In other words, before the results have come back, the alert(b) line is already being called. You need to put that alert line into the callback function after outputGeo(a).

Javascript’s a funny language. This async thing bit me until I researched JSONP and the synchrony of Javascript. I suggest you do the same. A great way to learn about this is to write a JSONP-request wrapper of your own. (Just a thought.)