google maps MySQL lat lng to JavaScript

Question

I have fixed latitude, and longitude (lat, lng) values in my SQL database. Now I want to do following: when I enter the name of the city in the searchbox, on an onClick event it sends the data via POST to the php file, and makes a SQL query which returns the lat, lng data. I want to call the JavaScript function for loading the map with the lat, lng parameters from the PHP file. I want all this to happen on a simple onClick event.

Here is my JavaScript function which is supposed to initialize the map (the load() function):

function getFile() {
  if (window.XMLHttpRequest) {              
    AJAX=new XMLHttpRequest();              
  } else {                                  
    AJAX=new ActiveXObject("Microsoft.XMLHTTP");
  }
  if (AJAX) {
    var searchField = document.getElementById("searchField");

    AJAX.open("POST", "gmap.php", false);                             
    AJAX.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
    AJAX.setRequestHeader("Content-length", searchField.value.length);
    AJAX.setRequestHeader("Connection", "close");
         AJAX.send("foo=" + searchField.value);
     return load(AJAX.responseText);   

  } else {
     return false;
  }                                             
}

And here is my gmap.php file:

<?php
header( 'Content-Type: text/html; charset=UTF-8' );
mb_internal_encoding( 'UTF-8' );
$a = $_POST['searchField'];
$dbhost = "localhost";
$dbuser = "*******";
$dbpass = "*******";
$dbname = "citydb";



    //connect sql
mysql_connect($dbhost, $dbuser, $dbpass);

    //select db
mysql_select_db($dbname) or die(mysql_error());
    //retrieve data
//$city=$_GET['city'];
    //escape user input to help prevent SQL injection
//$city=mysql_real_escape_string($city);
    //query
mysql_query('SET CHARACTER SET utf8');
$result=mysql_query("SELECT citystart, cityend FROM cityids WHERE city='$a' ");
if(!result) {

    die("Database query failed: " . myql_error());
    }

while($row=mysql_fetch_array($result)) {


    $lat=$row['citystart'];
    $lng=$row['cityend'];

Here is the onClick call:

<input type="submit" class="regular" name="FindEv" value="FindEv" onClick="getFile(); return false;" />

The problem is that the JavaScript function load() is called before the PHP data has returned. I've spend over a week now to figure this out, but I cannot find the solution. I've tried eval(), I've also tried to call the load() function from PHP, which also failed because it is inside an onClick event, which is inside a div, so the load() function doesn't execute, it is only displayed inside the div, when I go on Inspect element i Firebug.

I'm talking about lat, lng values for GLatLng().

shinjuo · Accepted Answer · 2010-11-24 20:37:51Z

I actually did sort of the same thing with mysql. The google map API I used was a little different though.

    <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
    <meta http-equiv="content-type" content="text/html; charset=utf-8"/>
    <title>Google Map API Test</title>
    <script src="http://maps.google.com/maps?file=api&v=2&key=ABQIAAAAh6DEO6zsM8Xua6WBNm-dbBRD8yUxCv4Esyhw4vpb86bE3mijaBS3Fcz1Rq_adaGcRea0Mlr9lNqAJw"
            type="text/javascript"></script>

    <script type="text/javascript">
    //<![CDATA[

    var iconBlue = new GIcon(); 
    iconBlue.image = 'http://labs.google.com/ridefinder/images/mm_20_blue.png';
    iconBlue.shadow = 'http://labs.google.com/ridefinder/images/mm_20_shadow.png';
    iconBlue.iconSize = new GSize(12, 20);
    iconBlue.shadowSize = new GSize(22, 20);
    iconBlue.iconAnchor = new GPoint(6, 20);
    iconBlue.infoWindowAnchor = new GPoint(5, 1);

    var iconRed = new GIcon(); 
    iconRed.image = 'http://labs.google.com/ridefinder/images/mm_20_red.png';
    iconRed.shadow = 'http://labs.google.com/ridefinder/images/mm_20_shadow.png';
    iconRed.iconSize = new GSize(12, 20);
    iconRed.shadowSize = new GSize(22, 20);
    iconRed.iconAnchor = new GPoint(6, 20);
    iconRed.infoWindowAnchor = new GPoint(5, 1);

    var iconYellow = new GIcon(); 
    iconYellow.image = 'http://labs.google.com/ridefinder/images/mm_20_yellow.png';
    iconYellow.shadow = 'http://labs.google.com/ridefinder/images/mm_20_shadow.png';
    iconYellow.iconSize = new GSize(12, 20);
    iconYellow.shadowSize = new GSize(22, 20);
    iconYellow.iconAnchor = new GPoint(6, 20);
    iconYellow.infoWindowAnchor = new GPoint(5, 1);

    var iconGreen = new GIcon(); 
    iconGreen.image = 'http://labs.google.com/ridefinder/images/mm_20_green.png';
    iconGreen.shadow = 'http://labs.google.com/ridefinder/images/mm_20_shadow.png';
    iconGreen.iconSize = new GSize(12, 20);
    iconGreen.shadowSize = new GSize(22, 20);
    iconGreen.iconAnchor = new GPoint(6, 20);
    iconGreen.infoWindowAnchor = new GPoint(5, 1);

    var customIcons = [];
    customIcons["175"] = iconGreen;
    customIcons["200"] = iconGreen;
    customIcons["225"] = iconGreen;
    customIcons["250"] = iconBlue;
    customIcons["275"] = iconBlue;
    customIcons["300"] = iconBlue;
    customIcons["325"] = iconRed;
    customIcons["350"] = iconRed;
    customIcons["375"] = iconRed;
    customIcons["100"] = iconYellow;
    customIcons["125"] = iconYellow;
    customIcons["150"] = iconYellow;

    function load() {
      if (GBrowserIsCompatible()) {
        var map = new GMap2(document.getElementById("map"));
        map.addControl(new GSmallMapControl());
        map.addControl(new GMapTypeControl());
        map.setCenter(new GLatLng(39.8163, -98.55762), 4);

        GDownloadUrl("markerData.php", function(data) {
          var xml = GXml.parse(data);
          var markers = xml.documentElement.getElementsByTagName("marker");
          for (var i = 0; i < markers.length; i++) {
            var mapTime = markers[i].getAttribute("time");
            var mapSize = markers[i].getAttribute("size");
            var mapCity = markers[i].getAttribute("city");
            var mapState = markers[i].getAttribute("state");
            var mapPop = markers[i].getAttribute("pop");
            var type = markers[i].getAttribute("size");
            var mapComments = markers[i].getAttribute("comments");
            var point = new GLatLng(parseFloat(markers[i].getAttribute("lat")),
                                    parseFloat(markers[i].getAttribute("lng")));
            var marker = createMarker(point, mapTime, mapSize, mapCity, mapState, mapPop, mapComments, type);
            map.addOverlay(marker);
          }
        });
      }
    }

    function createMarker(point, mapTime, mapSize, mapCity, mapState, mapPop, mapComments, type) {
      var marker = new GMarker(point, customIcons[type]);
      var html = "Time: " + mapTime + "<br/>" + "Size: " + mapSize + "<br/>" + "Location: " + mapCity + ", " + mapState + "<br/>" + "Population: " + mapPop + "<br/>" + "Comments: " + mapComments;
      GEvent.addListener(marker, 'click', function() {
        marker.openInfoWindowHtml(html);
      });
      return marker;
    }
    //]]>
  </script>

  </head>

  <body onload="load()" onunload="GUnload()">
    <div id="map" style="width: 750px; height: 500px"></div>
    <div style="width: 750px; text-align: center"><img src="http://labs.google.com/ridefinder/images/mm_20_yellow.png" /> Less than 1.75"&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
         <img src="http://labs.google.com/ridefinder/images/mm_20_green.png" /> 1.75" - 2.25"&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
         <img src="http://labs.google.com/ridefinder/images/mm_20_blue.png" />2.50" - 3.00"&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
         <img src="http://labs.google.com/ridefinder/images/mm_20_red.png" />3.25" - 3.75"
    </div>
  </body>
</html>

Map Info.php create_element("markers"); $parnode = $doc->append_child($node);

// Opens a connection to a MySQL server
$connection=mysql_connect ($host, $username, $password);
if (!$connection) {
    die('Not connected : ' . mysql_error()); 
}

// Set the active MySQL database 
$db_selected = mysql_select_db($database, $connection); 
if (!$db_selected) { 
    die ('Can\'t use db : ' . mysql_error()); 
}// Select all the rows in the markers table 
$query = "SELECT * FROM mapData 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 = $doc->create_element("marker");
    $newnode = $parnode->append_child($node);
    $newnode->set_attribute("time", $row['Time']);
    $newnode->set_attribute("size", $row['Size']);
    $newnode->set_attribute("city", $row['City']);
    $newnode->set_attribute("state", $row['State']);
    $newnode->set_attribute("pop", $row['Population']);
    $newnode->set_attribute("comments", $row['Comments']);
    $newnode->set_attribute("lat", $row['Latitude']);
    $newnode->set_attribute("lng", $row['Longitude']);
}
$xmlfile = $doc->dump_mem(); echo $xmlfile;

?>

Yes, but you have fixed GLatLng(39.8163, -98.55762), i want this values (39.8163, -98.55762) to be read from SQL...
I see what you mean. let me see if I can make it move to those points with my lat lon reading

simshaun · Accepted Answer · 2010-11-24 20:38:45Z

2

AJAX (keyword asynchronous) doesn't block the rest of the script from executing as you are expecting it to.

You have to check for a completed request using the onreadystatechange method...

AJAX.onreadystatechange = function() {
    if (AJAX.readyState == 4 && AJAX.status == 200) {
        load(AJAX.responseText);
    }
}

answered Nov 24, 2010 at 20:38

simshaun

21.5k1 gold badge60 silver badges73 bronze badges

3 Comments

digitale Over a year ago

I've tried this earlier, same thing, the load() function executes before the php values are passed...

simshaun Over a year ago

Did you remove the "return load(...)" line? If so, is load() called anywhere else? In the code I provided, it will only fire after PHP has returned values. Therefore, something else is wrong.

digitale Over a year ago

It isn't called anywhere else. I've really tried everything. I know, but it seems that it doesn't. The php file is ok, I've tested it several times...

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