Just an example of adding Google Maps to webpage with markers (no jQuery required)

google-map-with-markers.js

function initializeMaps() {
  var GOOGLE_API_KEY = "";

  var location = "Bristol";
  var country  = "UK";

  var geocoder     = new google.maps.Geocoder();
  var markerBounds = new google.maps.LatLngBounds();

  var map = new google.maps.Map(document.getElementById( "map_canvas" ), {
    zoom:      13,
    mapTypeId: google.maps.MapTypeId.ROADMAP
  });

  geocoder.geocode({
    'address': location + ", " + country
  }, function ( results, status ) {
    if ( status == google.maps.GeocoderStatus.OK ) {
      console.log( "centering map on given location" );
      console.log( results[0].geometry.location );
      map.setCenter( results[0].geometry.location );
    } else {
      map.setCenter( new google.maps.LatLng( 51.5137379,-0.1390374 ));
      map.setZoom(5);
    }
  });

  var addressArray = new Array(
    'BS8+1TH',  // university
    'BS48+3DY', // airport
    'BS1+5TJ'   // cathedral
  );
    
  for ( var i = addressArray.length; i > 0; i-- ) {
    geocoder.geocode({
      'address': addressArray[i]
    }, function ( results, status ) {
      if ( status == google.maps.GeocoderStatus.OK ) {
        console.log( "adding markers" );
        console.log( results[0].geometry.location );
        var marker = new google.maps.Marker({
          map:       map,
          position:  results[0].geometry.location,
          icon:      'http://maps.google.com/mapfiles/ms/icons/purple-dot.png',
          animation: google.maps.Animation.DROP
        });
        markerBounds.extend( results[0].geometry.location );
        map.fitBounds( markerBounds );
      }
    });
  }
}

function loadGoogleMaps() {
  var script  = document.createElement( "script" );
  script.type = "text/javascript";
  script.src  = "//maps.googleapis.com/maps/api/js?key=" + GOOGLE_API_KEY + "&sensor=true&callback=initializeMaps";
  document.body.appendChild( script );
}

if ( window.addEventListener ) {
  window.addEventListener( 'load', loadGoogleMaps, false );
} else if ( window.attachEvent ) {
  window.attachEvent( 'onload', loadGoogleMaps );
}