Marker at map problem

I have map on my si开发者_开发百科te but I don't kno how to add marker at this location (42.9967, 21.941667). Any help?

<script type="text/javascript">
    function init() {
        var mapDiv = document.getElementById('map');
        var latlng = new google.maps.LatLng(42.9967, 21.941667);
        var options = {
            center: latlng,
            zoom: 15,
            mapTypeId: google.maps.MapTypeId.ROADMAP
        };
        var map = new google.maps.Map(mapDiv, options);

    };
    $(document).ready(init);
</script>

---

Check this out:

  var myLatlng = new google.maps.LatLng(-25.363882,131.044922);
  var myOptions = {
    zoom: 4,
    center: myLatlng,
    mapTypeId: google.maps.MapTypeId.ROADMAP,
  }
 var map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);

 var marker = new google.maps.Marker({
      position: myLatlng,
      title:"Hello World!"
  });

  // To add the marker to the map, call setMap();
  marker.setMap(map);  

---

You've created the map and set the center, but you haven't actually created a marker.

var marker = new google.maps.Marker({
    position: latlng, 
    map: map, 
    title:"Hello World!"