var txt_overlay; 
function initialize() {
    var titi =  new Array();
    if (GBrowserIsCompatible()) {
        var map = new GMap2(document.getElementById("map_canvas"));
        /*http://maps.google.fr/maps?f=q&source=s_q&hl=fr&geocode=&q=&ie=UTF8&ll=49.968889,3.045959&spn=2.331994,4.943848&z=8*/
        map.setCenter(new GLatLng(50.308889, 2.878418), 8);
        map.addControl(new GSmallMapControl());
        map.addControl(new GMapTypeControl());
                              
        GDownloadUrl("points_relais.xml", function(data) {     
            var xml = GXml.parse(data);
            var markers = xml.documentElement.getElementsByTagName("marker");
            for (var i = 0; i < markers.length; i++) 
            {                                                     
                latlng = new GLatLng(parseFloat(markers[i].getAttribute("lat")),
                parseFloat(markers[i].getAttribute("lng")));
                var marker = new GMarker(latlng);
                var txt_overlay = "<b>"+markers[i].getAttribute("nom")+"</b><br/>"+markers[i].getAttribute("addr")+"<br/>"+markers[i].getAttribute("cp")+" "+markers[i].getAttribute("ville");
                map.addOverlay(createMarker(latlng,txt_overlay));
            }
        });
    }

    function createMarker(point, text) {
        var marker = new GMarker(point);
        GEvent.addListener(marker, "click", function() {
            map.openInfoWindowHtml(point, text);
        });
    return marker;
    }
}