url.com?postcode=XXXXXX

center: new google.maps.LatLng(longitude, latitude)

var postcodeValue = $('#map').attr('data-postcode');
  function latLong(location, callback) {
  var geocoder = new google.maps.Geocoder();
  var address = location;
  var longitude;
  var latitude;
  geocoder.geocode({
    'address': address
  }, function (results, status) {
    if (status == google.maps.GeocoderStatus.OK) {
      latitude = results[0].geometry.location.lat();
      longitude = results[0].geometry.location.lng();
      callback(latitude, longitude);
    }
  });
}

latLong(postcodeValue, function(lat, lon) {
  console.log(lat);
  console.log(lon);
});

var options = {
  mapTypeControlOptions: {
    mapTypeIds: [ 'Styled']
  },
  center: new google.maps.LatLng(latLong),
  zoom: 12,
  mapTypeId: 'Styled',
  disableDefaultUI: true,
  draggable: false,
  disableDoubleClickZoom: true
};

var div = document.getElementById('map');
var map = new google.maps.Map(div, options);
var styledMapType = new google.maps.StyledMapType(styles);

map.mapTypes.set('Styled', styledMapType);