GMaps Geocoding - Script Not Waiting For Result

We have an address that we are submitting to GMaps API for geocoding. When the form is submitted, the address is supposed to become geocoded via javascript, 2 hidden form values for lat and long are supposed to populate with the geocoded result, and then the form is submitted for a back-end script to write to an xml file. The problem that I'm having is that there seems to be a lag with the call to GClientGeocoder and the script continues to process without waiting for a "result." How can I make it so that the javascript "waits" for a proper GClientGeocoder response so that the hidden form fields receive values before the scripts finishes executing.

More generally, I always thought that javascript executed sequentially, as in:
do something(variable, functionThis())
do somethingElse
In this example, I thought that functionThis() would have to finish executing before the script would move onto "do somethingElse."

The location of the script: [URL]
-OR-
The wretched Javascript with issues:
var map = null;
var geocoder = null;
var rtnValue = false;
function initialize() {
if (GBrowserIsCompatible()) {
map = new GMap2(document.getElementById("map"));
map.setCenter(new google.maps.LatLng(34.145553,-118.118563), 14);
geocoder = new GClientGeocoder();
[Code] ......