center the map on marker key on google maps api 3

**Yousef Altaf** · Feb 8 '14, 03:36 PM

Hi all I am working on google map api-3 and I have two interface one is inserting data to my database and second getting the data on my site from my database now everything is working fine I insert the data to my databse and getting it but here is the problem I need to center the map on the marker key on the map

here is my code

to insert the data

php code

Code:

<?php
// Gets data from URL parameters
$name = $_GET['name'];
$address = $_GET['address'];
$lat = $_GET['lat'];
$lng = $_GET['lng'];
$type = $_GET['type'];

mysql_connect("localhost", "root", "") or
         die("Could not connect: " . mysql_error());
mysql_select_db("arabia");

// Insert new row with user data
$query = sprintf("INSERT INTO markers " .
         " (id, name, address, lat, lng, type ) " .
         " VALUES (NULL, '%s', '%s', '%s', '%s', '%s');",
         mysql_real_escape_string($name),
         mysql_real_escape_string($address),
         mysql_real_escape_string($lat),
         mysql_real_escape_string($lng),
         mysql_real_escape_string($type));

$result = mysql_query($query);

if (!$result) {
  die('Invalid query: ' . mysql_error());
}

?>

and this is the HTML code

Code:

<!DOCTYPE html >
  <head>
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no" />
    <meta http-equiv="content-type" content="text/html; charset=UTF-8"/>
    <title>Google Maps JavaScript API v3 Example: Map Simple</title>
    <script type="text/javascript" src="http://maps.googleapis.com/maps/api/js?sensor=true"></script>
    <script type="text/javascript">
    var marker;
    var infowindow;

    function initialize() {
      var latlng = new google.maps.LatLng(30.0599153,31.2620199,13);
      var options = {
        zoom: 13,
        center: latlng,
        mapTypeId: google.maps.MapTypeId.ROADMAP
      }
      var map = new google.maps.Map(document.getElementById("map-canvas"), options);
      var html = "<table>" +
                 "<tr><td>Name:</td> <td><input type='text' id='name'/> </td> </tr>" +
                 "<tr><td>Address:</td> <td><input type='text' id='address'/></td> </tr>" +
                 "<tr><td>Type:</td> <td><select id='type'>" +
                 "<option value='bar' SELECTED>bar</option>" +
                 "<option value='restaurant'>restaurant</option>" +
                 "</select> </td></tr>" +
                 "<tr><td></td><td><input type='button' value='Save & Close' onclick='saveData()'/></td></tr>";
    infowindow = new google.maps.InfoWindow({
     content: html
    });
 
    google.maps.event.addListener(map, "click", function(event) {
        marker = new google.maps.Marker({
          position: event.latLng,
          map: map
        });
        google.maps.event.addListener(marker, "click", function() {
          infowindow.open(map, marker);
        });
    });
    }

    function saveData() {
      var name = escape(document.getElementById("name").value);
      var address = escape(document.getElementById("address").value);
      var type = document.getElementById("type").value;
      var latlng = marker.getPosition();
 
      var url = "phpsqlinfo_addrow.php?name=" + name + "&address=" + address +
                "&type=" + type + "&lat=" + latlng.lat() + "&lng=" + latlng.lng();
      downloadUrl(url, function(data, responseCode) {
        if (responseCode == 200 && data.length <= 1) {
          infowindow.close();
          document.getElementById("message").innerHTML = "Location added.";
        }
      });
    }

    function downloadUrl(url, callback) {
      var request = window.ActiveXObject ?
          new ActiveXObject('Microsoft.XMLHTTP') :
          new XMLHttpRequest;

      request.onreadystatechange = function() {
        if (request.readyState == 4) {
          request.onreadystatechange = doNothing;
          callback(request.responseText, request.status);
        }
      };

      request.open('GET', url, true);
      request.send(null);
    }

    function doNothing() {}
    </script>
  </head>

  <body style="margin:0px; padding:0px;" onload="initialize()">
    <div id="map-canvas" style="width: 800px; height: 600px"></div>
    <div id="message"></div>
  </body>

</html>

now this is getting data from the db code

php code

Code:

<?php  

// Start XML file, create parent node

$dom = new DOMDocument("1.0");
$node = $dom->createElement("markers");
$parnode = $dom->appendChild($node); 

// Opens a connection to a MySQL server

mysql_connect("localhost", "root", "") or
         die("Could not connect: " . mysql_error());
mysql_select_db("arabia");

// Select all the rows in the markers table

$query = "SELECT * FROM markers WHERE 1";
$result = mysql_query($query);
if (!$result) {  
  die('Invalid query: ' . mysql_error());
} 

header("Content-type: text/xml"); 

// Iterate through the rows, adding XML nodes for each

while ($row = @mysql_fetch_assoc($result)){  
  // ADD TO XML DOCUMENT NODE  
  $node = $dom->createElement("marker");  
  $newnode = $parnode->appendChild($node);   
  $newnode->setAttribute("name",$row['name']);
  $newnode->setAttribute("address", $row['address']);  
  $newnode->setAttribute("lat", $row['lat']);  
  $newnode->setAttribute("lng", $row['lng']);  
  $newnode->setAttribute("type", $row['type']);
} 

echo $dom->saveXML();

?>

and the html code

Code:

<!DOCTYPE html >
  <head>
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no" />
    <meta http-equiv="content-type" content="text/html; charset=UTF-8"/>
    <title>map</title>
    <script type="text/javascript" src="http://maps.googleapis.com/maps/api/js?sensor=false"></script>
    <script type="text/javascript">
    //<![CDATA[

    var customIcons = {
      restaurant: {
        icon: 'http://labs.google.com/ridefinder/images/mm_20_blue.png'
      },
      bar: {
        icon: 'http://labs.google.com/ridefinder/images/mm_20_red.png'
      }
    };
    function load() {
      var map = new google.maps.Map(document.getElementById("map"), {
        center: new google.maps.LatLng(30.0599153,31.2620199,13)||map.setCenter(marker.getPosition()),
        zoom: 13,
        mapTypeId: 'roadmap'
      });
      var infoWindow = new google.maps.InfoWindow;

      // Change this depending on the name of your PHP file
      downloadUrl("phpsqlajax_genxml.php", function(data) {
        var xml = data.responseXML;
        var markers = xml.documentElement.getElementsByTagName("marker");
        for (var i = 0; i < markers.length; i++) {
          var name = markers[i].getAttribute("name");
          var address = markers[i].getAttribute("address");
          var type = markers[i].getAttribute("type");
          var point = new google.maps.LatLng(
              parseFloat(markers[i].getAttribute("lat")),
              parseFloat(markers[i].getAttribute("lng")));
          var html = "<b>" + name + "</b> <br/>" + address;
          var icon = customIcons[type] || {};
          var marker = new google.maps.Marker({
            map: map,
            position: point,
            icon: icon.icon
          });
          bindInfoWindow(marker, map, infoWindow, html);
        }
      });
    }

    function bindInfoWindow(marker, map, infoWindow, html) {
      google.maps.event.addListener(marker, 'click', function() {
        infoWindow.setContent(html);
        infoWindow.open(map, marker);
      });
    }

    function downloadUrl(url, callback) {
      var request = window.ActiveXObject ?
          new ActiveXObject('Microsoft.XMLHTTP') :
          new XMLHttpRequest;

      request.onreadystatechange = function() {
        if (request.readyState == 4) {
          request.onreadystatechange = doNothing;
          callback(request, request.status);
        }
      };

      request.open('GET', url, true);
      request.send(null);
    }

    function doNothing() {}

    //]]>

  </script>

  </head>

  <body onload="load()">
    <div id="map" style="width: 500px; height: 300px"></div>
  </body>

</html>

now how to center the map on the key