change the place of the marker with the click - google-maps

Question

i am working on google maps, what i want to do is to click on the map it add a marker to the map its working fine but the problem is that i need to move the same marker to a new place if i click some where else instead of new marker. and also when i click on any point it give me the address of that place in a text field
here is my code
<script type="text/javascript">
var map;
var markersArray = [];
function initialize() {
var haightAshbury = new google.maps.LatLng(37.7699298, -122.4469157);
var mapOptions = {
zoom: 7,
center: haightAshbury,
mapTypeId: google.maps.MapTypeId.ROADMAP
};
map = new google.maps.Map(document.getElementById("map_canvas"), mapOptions);
google.maps.event.addListenerOnce(map, 'click', function(event) {
addMarker(event.latLng);
});
}
function addMarker(location) {
marker = new google.maps.Marker({
position: location,
map: map
});
markersArray.push(marker);
}
// Removes the overlays from the map, but keeps them in the array
function clearOverlays() {
if (markersArray) {
for (i in markersArray) {
markersArray[i].setMap(null);
}
}
}
}

Answer 1

You can call clearOverlays anytime you create a new marker.this way you hide the previous marker and only the new is shown.
another way is to have a var marker just as you have a var map. you can edit the markers position in addMarker.
as far as geocoding is concerned take a look at this