Question

I’m developing a web page with a Google Maps application and there is something that I’m having trouble with. As it stands, the web page has a functional map (without any layers) and a search bar. I’m new to programming so hopefully there is a quick fix that I’m missing.

When I look up an address, the placemark is is positioned where it is supposed to be. However, when I make a second search with a different address, the placemark of the first search remains visible so that there are two placemarks on the screen. How can I make a new placemark replace the old one?

<script type="text/javascript">
    var geocoder;
    var map; 
    var marker;
  function initialize() {
    geocoder = new google.maps.Geocoder ();
    var latlng = new google.maps.LatLng (55.1667, -114.4000);
    var myOptions = {
      zoom: 5,
      center: latlng,
      mapTypeId: google.maps.MapTypeId.ROADMAP
    }
     map = new google.maps.Map(document.getElementById("map_canvas"),
        myOptions);
    marker = new google.maps.Marker({map:map});
        }
    function codeAddress () {
        var address = document.getElementById ("address").value;
        geocoder.geocode ( { 'address': address}, function(results, status)                              {
        if (status == google.maps.GeocoderStatus.OK)  {
            map.setCenter(results [0].geometry.location);
            marker.setposition(results [0].geometry.location);
            map.setZoom(16);
            } 
        else {
            alert("Geocode was not successful for the following reason: " + status);
                }
    }); 
                            }
</script>

Answer 1

One way to achieve what you describe is with a global marker variable. Since the codeAddress function is calling new google.maps.Marker every time it runs, you will get a new marker each time.

Instead, use the setPosition function of the global marker to move it around.

    var geocoder;
    var map; 

    // ADDED
    var marker;

  function initialize() {
    geocoder = new google.maps.Geocoder ();
    var latlng = new google.maps.LatLng (55.1667, -114.4000);
    var myOptions = {
      zoom: 5,
      center: latlng,
      mapTypeId: google.maps.MapTypeId.ROADMAP
    }
     map = new google.maps.Map(document.getElementById("map_canvas"),
        myOptions);

     // ADDED
     marker = new google.maps.Marker({ map: map });
  }
    function codeAddress () {
        var address = document.getElementById ("address").value;
        geocoder.geocode ( { 'address': address}, function(results, status)  {
        if (status == google.maps.GeocoderStatus.OK)  {
            map.setCenter(results [0].geometry.location);

            // CHANGED
            marker.setPosition(results [0].geometry.location);

            map.setZoom(16);
        } 
        else {
            alert("Geocode was not successful for the following reason: " + status);
        }
    }); 
}