function initialize() {
  if (GBrowserIsCompatible()) {
    var map = new GMap2(document.getElementById("map_canvas"));
    map.setCenter(new GLatLng(44.22474, 4.485748), 7);
    map.setUIToDefault();
    var baseIcon = new GIcon(G_DEFAULT_ICON);
    baseIcon.shadow = "http://www.google.com/mapfiles/shadow50.png";
    baseIcon.iconSize = new GSize(20, 34);
    baseIcon.shadowSize = new GSize(37, 34);
    markerOptions = { icon:baseIcon };
    map.addOverlay(new GMarker(new GLatLng(44.22474, 4.485748), markerOptions ));
  }
}

    window.onload = function () {
        initialize()
    }
    window.onunload = function () {
        GUnload()
    }