function initMap() {
  var pointA = new google.maps.LatLng(51.2750, 1.0870),
    pointC = new google.maps.LatLng(50.8429, -0.1313),
    pointB = new google.maps.LatLng(51.5379, 0.7138),
    myOptions = {
      zoom: 7,
      center: pointA,
      mapTypeId: google.maps.MapTypeId.ROADMAP
    },
    map = new google.maps.Map(document.getElementById('map-canvas'), myOptions),
    markerA = new google.maps.Marker({
      position: pointA,
      title: "point A",
      label: "AAA",
      map: map
    }),
    markerB = new google.maps.Marker({
      position: pointB,
      title: "point B",
      label: "B",
      map: map
    }),
    markerC = new google.maps.Marker({
      position: pointC,
      title: "point C",
      label: "C",
      map: map
    });
}

initMap();