Updating Changing Coordinates of Markers "Live" on a Google Map from MySQL Database

Question

I am trying to find a solution that will allow me to plot the GPS coordinates of many moving objects "live" on a Google Map.
The GPS coordinates of each object will constantly be updating into a MySQL database, and I want to read each updated coordinate, once every three of seconds, and re-plot the marker coordinates on the Google Map, without the user having to refresh the page.
I have a code that receives data from the database,and Database information is read every 3 seconds with setInterval.
My problem is here: With each setinterval load New database data is not read.that's mean Database information is read once and does not receive any new information. How can I fix this problem?

<?php
    include "db_connect.php";
    $sql="SELECT * FROM temperature_details ORDER BY id DESC LIMIT 1 ";
    $result=mysql_query($sql);
    $firstrow = mysql_fetch_assoc($result);
    function getNewLat(){
        $sql="SELECT * FROM temperature_details ORDER BY id DESC LIMIT 1 ";
        $result=mysql_query($sql);
        $lat = mysql_fetch_assoc($result);
        return $lat['latitude'];
    }
    function getNewLang(){
        $sql="SELECT * FROM temperature_details ORDER BY id DESC LIMIT 1 ";
        $result=mysql_query($sql);
        $Lang = mysql_fetch_assoc($result);
        return $Lang['longitude'];
    }
?>
<script src="http://maps.googleapis.com/maps/api/js?key=API_KEY&libraries=geometry"></script>
    <div id="map" style="height:500px;width:100%;" ></div>

<script>
    function initialize() {
        var myLatLng = new google.maps.LatLng({lat:<?php echo .$firstrow['latitude'];?>, lng: <?php echo .$firstrow['longitude'];?>}),
        myOptions = {
            zoom: 16,
            center: myLatLng,
            mapTypeId: google.maps.MapTypeId.ROADMAP
        },
        map = new google.maps.Map( document.getElementById( 'map' ), myOptions   ),
        marker = new google.maps.Marker( {position: myLatLng, map: map} );
        marker.setMap( map );
        moveMarker( map, marker );
    }
    function moveMarker( map,marker ) {
        setInterval( function(){ 
            marker.setPosition(new google.maps.LatLng( {lat:<?php echo getNewLat();?>, lng: <?php echo getNewLang();?>} ));
            map.panTo( new google.maps.LatLng(  {lat:<?php echo getNewLat();?>, lng: <?php echo getNewLang();?>} ));
            console.log("I am working");
        }, 3000 );
    };
    initialize();
</script> 

Answer 1

i can to resolve it.

function moveMarker(){
  setInterval( function(){ 
      $.get("point", function(data){
      var mydata= $.parseJSON(data);
      var art1 = mydata.lat;  // <-----------  access the element
      var art2 = mydata.lng;
      marker.setPosition( new google.maps.LatLng( {lat:art1 , lng: art2} ) );
      map.panTo( new google.maps.LatLng( {lat:art1 , lng: art2} ));

    });
}, 3000 );

In the above code,"point" is a page ,It receives the coordinates as a query with laravel framwork

<?php
use App\MoteharekModel;
  $lt = MoteharekModel::orderby('id','desc')->first();
  echo json_encode($lt);
?>