php/mysql inside javascript function

Question

I am trying to add markers to a google map but need to bring lat/lng values in from php/mysql. The code I have below is not working, just wondering if I am going about this the right way! Thanks!

function addMarker(lat, lng){

        var point = new google.maps.LatLng(lat, lng);
        var marker = new google.maps.Marker({
            position: point,
            map: map
        });

    }
    function initialize() {
        var mapOptions = {
            center: {lat: 54.872128, lng: -6.284874},
            zoom: 15
        };

        map = new google.maps.Map(document.getElementById('map-canvas'),
                mapOptions);

                 <?php
                $query = mysql_query("select * from tester");
                while($row = mysql_fetch_array($query)){
                    $lat = $row['lat'];
                    $lng = $row['lng'];
                    echo ("addMarker($lat, $lng);");
                }
                ?>

    }