test adresse:
<input type="text" id="address" onchange="doGeocode()" /> 

<!-- require Google Maps API --> 

<script src="//maps.googleapis.com/maps/api/js"></script>



<script>
function doGeocode() { 
  var addr = document.getElementById("address"); // Get geocoder instance 
  var geocoder = new google.maps.Geocoder(); // Geocode the address 
  geocoder.geocode({ 
    'address': addr.value 
  }, 
  function(results, status) { 
    if (status === google.maps.GeocoderStatus.OK && results.length > 0) { // set it to the correct, formatted address if it's valid 
      addr.value = results[0].formatted_address;; // show an error if it's not 
    } else 
      alert("Invalid address"); 
    }); 
};

</script>