<script>
                jQuery(document).ready(function(){
                    var jsapiKey = "YOUR API KEY";
                    var address = "YOUR+ADDRESS";
                    jQuery.getJSON("http://maps.google.com/maps/geo?q="+address+"&key="+jsapiKey+"&sensor=true&output=json&callback=?",
                      function(data, textStatus){
                         console.log("Latitude: "+data.Placemark[0].Point.coordinates[1]);
                         console.log("Longitude: "+data.Placemark[0].Point.coordinates[0]);
                      });
                  });
            </script>

Nice ajax function to grab the latitude and longitude of an address or postcode. Don't forget your google key and address formatting.

Get Latitude and Longitude using jQuery and Googles Geo Coding Service

jQuery