I am also a beginner, but I hope to help, You can use something like:
ASP Code:
<select id="address1" value="Geocode" onchange="codeAddress('address1')">
<option>Select</option>
<option value="Alabama,AL">Alabama</option>
<option value="Alaska,AK">Alaska</option>
<option value="Arizona,AZ">Arizona</option>
</select>
<select id="address2" value="Geocode" onchange="codeAddress('address2')">
<option>Select</option>
<option value="Alberta,AB">Alberta</option>
</select></select>
Javascript Code:
function codeAddress(element) {
var address = document.getElementById(element).value;
geocoder.geocode({
'address': address
}, function (results, status) {
if (status == google.maps.GeocoderStatus.OK) {
map.setCenter(results[0].geometry.location);
map.setZoom(7);
} else {
alert('Geocode was not successful for the following reason: ' + status);
}
});
}