function load() {

  if (GBrowserIsCompatible()) {

    //icono
    var icon = new GIcon();
    icon.image = "http://www.sennutricion.org/images/icono_map.png";
    icon.iconSize = new GSize(40, 40);
    icon.iconAnchor = new GPoint(20, 40); 
    icon.infoWindowAnchor = new GPoint(30, 15); // Coordenadas de la viñeta

    var map = new GMap2(document.getElementById("map"));
    map.setCenter(new GLatLng(40.435699, -3.702342), 16);

    //creamos la marca
    var marker = new GMarker(new GLatLng(40.435699, -3.702342),icon);
    GEvent.addListener(marker, "click", function() {
        marker.openInfoWindowTabsHtml(infoTabs);
    });

    //la añadimos al mapa
    map.addOverlay(marker);
    map.addControl(new GSmallZoomControl());

  }

}

function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      if (oldonload) {
        oldonload();
      }
      func();
    }
  }
}

addLoadEvent(load);