var map;
var centerLatitude = 40.6897;
var centerLongitude = -95.0446;
var startZoom = 3;

   function addMarker(latitude, longitude, description) {
       var marker = new GMarker(new GLatLng(latitude, longitude));
       GEvent.addListener(marker, 'click',
           function() {
              marker.openInfoWindowHtml(description);
           }
       );
       map.addOverlay(marker);
   }
   
   function init() {
       if (GBrowserIsCompatible()) {
           map = new GMap2(document.getElementById("map"));
           map.addControl(new GSmallMapControl());
           map.setCenter(new GLatLng(centerLatitude, centerLongitude), startZoom);
           for(i=0; i<markers.size; i++) {
              addMarker(markers[i].latitude, markers[i].longitude, markers[i].name);
           }
       }
   }
   
   window.onload = init;
   window.onunload = GUnload;

   var markers = [
           {
              'latitude': 37.818361,
              'longitude': -122.478032,
              'name': 'Golden Gate Bridge'
           },
           {
              'latitude': 40.6897,
              'longitude': -74.0446,
              'name': 'Statue of Liberty'
           },
           {
              'latitude': 38.889166,
              'longitude': -77.035307,
              'name': 'Washington Monument'
           }
        ];