Solucionado les dejo el código completo:
Código HTML:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Documento sin título</title>
<script type="text/javascript">
function copiar(frm) {
frm.address.value = frm.provinciaList.value+' '+frm.localidadList.value+' '+frm.t3.value;
}
</script>
<script src="http://maps.google.com/maps?file=api&v=2&sensor=true
&key=ABQIAAAA8gk0hwIezlE4Mn3qRTySDhRDenltlsPu3NYhbY395MMDhCUItBQJ2hqC4ArFSPuYFwI8jNh3EyTJog"
type="text/javascript"></script>
<script type="text/javascript">
//<![CDATA[
// Inicialización de variables.
var map = null;
var geocoder = null;
function load() { // Abre LLAVE 1.
if (GBrowserIsCompatible()) { // Abre LLAVE 2.
map = new GMap2(document.getElementById("map"));
map.setCenter(new GLatLng(-38.00252047431972,-57.548789978027344), 12);
map.addControl(new GLargeMapControl());
map.addControl(new GMapTypeControl());
map.addControl(new GScaleControl());
geocoder = new GClientGeocoder();
//---------------------------------//
// MARCADOR AL HACER CLICK
//---------------------------------//
GEvent.addListener(map, "click",
function(marker, point) {
if (marker) {
null;
} else {
map.clearOverlays();
var marcador = new GMarker(point);
map.addOverlay(marcador);
//marcador.openInfoWindowHtml("<b><br>Coordenadas:<br></b>Latitud : "+point.y+"<br>Longitud : "+point.x+"<a href=http://www.mundivideo.com/fotos_pano.htm?lat="+point.y+"&lon="+point.x+"&mapa=3 TARGET=fijo><br><br>Fotografias</a>");
//marcador.openInfoWindowHtml("<b>Coordenadas:</b> "+point.y+","+point.x);
document.form_mapa.coordenadas.value = point.y+","+point.x;
}
}
);
getMarkers();
GEvent.addListener(map, "click", function(overlay, point) {
if (overlay){ // marker clicked
overlay.openInfoWindowHtml(overlay.infowindow); // open InfoWindow
} else if (point) { // background clicked
}
})
//---------------------------------//
// FIN MARCADOR AL HACER CLICK
//---------------------------------//
} // Cierra LLAVE 1.
} // Cierra LLAVE 2.
//---------------------------------//
// GEOCODER
//---------------------------------//
function showAddress(address, zoom) {
if (geocoder) {
geocoder.getLatLng(address,
function(point) {
if (!point) {
alert(address + " no se ha encontrado, si esta dirección existe y no aparece en el mapa situa manualmente el punto en el mapa haciendo click donde este la ubicación dejando los campos del formulario correctamente");
} else {
map.setCenter(point, zoom);
var marker = new GMarker(point);
map.addOverlay(marker);
//marker.openInfoWindowHtml("<b>"+address+"</b><br>Coordenadas:<br>Latitud : "+point.y+"<br>Longitud : "+point.x+"<a href=http://www.mundivideo.com/fotos_pano.htm?lat="+point.y+"&lon="+point.x+"&mapa=3 TARGET=fijo><br><br>Fotografias</a>");
// marker.openInfoWindowHtml("<b>Coordenadas:</b> "+point.y+","+point.x);
document.form_mapa.coordenadas.value = point.y+","+point.x;
}
}
);
}}
//---------------------------------//
// FIN DE GEOCODER
//---------------------------------//
function getMarkers(){
var urlstr="mardel.php";
var request = GXmlHttp.create();
request.open('GET', urlstr , true); // request XML from PHP with AJAX call
request.onreadystatechange = function () {
if (request.readyState == 4) {
var xmlDoc = request.responseXML;
locations = xmlDoc.documentElement.getElementsByTagName("location");
markers = [];
if (locations.length){
for (var i = 0; i < locations.length; i++) { // cycle thru locations
markers[i] = new GMarker(new GLatLng(locations[i].getAttribute("lat"),locations[i].getAttribute("lng")));
// Add attributes to the marker so we can poll them later.
// When clicked, an overlay will have these properties.
markers[i].infowindow = locations[i].getAttribute("name");
// Useful things to store on a marker (Not needed for this example, could be removed)
// Tells you what index in the markers[] array an overlay is
markers[i].markerindex = i;
// Store the location_id of the location the marker represents.
// Very useful to know the true id of a marker, you could then make
// AJAX calls to the database to update the information if you had it's location_id
markers[i].db_id = locations[i].getAttribute("id");
map.addOverlay(markers[i]);
}
}
}
}
request.send(null);
}
//]]>
</script>
<script type="text/javascript" src="http://www.diariothc.com/wp-content/codes/animatedcollapse.js"></script>
<script src="http://maps.google.com/maps?file=api&v=2&sensor=true
&key=ABQIAAAA8gk0hwIezlE4Mn3qRTySDhRDenltlsPu3NYhbY395MMDhCUItBQJ2hqC4ArFSPuYFwI8jNh3EyTJog"
type="text/javascript"></script>
</head>
<body onLoad="load();" onunload="GUnload();">
<form name="form_mapa" action="#" onsubmit=" showAddress(this.address.value, this.zoom.value=parseFloat(this.zoom.value)); return false">
<input id="provinciaList" type="hidden" name="provinciaList" onkeyup="copiar(this.form)" />
<select name="localidadList" id="localidadList" onclick="copiar(this.form)" />
<option>Seleccione una localidad...</option>
<option>Mar del Plata</option>
<option>Mar de las Pampas</option>
<option>Ciudad Autonoma de Buenos Aires</option>
</select>
<input id="t3" type=text name="t3" onkeyup="copiar(this.form)" />
<input class="situar" type="submit" value="Situar en mapa" />
<input type="hidden" name="address" />
<input type="hidden" size="1" name="zoom" value=12 />
<div id="map" style="width: 432px; height: 300px"></div>
</form>
</body>
</html>