Return json data with php
<p>I want to return json data but my code is not working. I don't get any error message. I have index.php, ajax.php and db.php. Db.php is working. But my ajax code is not working. Where is my mistake?</p>

<p><strong>index.php:</strong></p>

<pre><code>&lt;!DOCTYPE html&gt;
&lt;html&gt;
&lt;head&gt;
&lt;script type="text/javascript" src="http://code.jquery.com/jquery.min.js"&gt;&lt;/script&gt;
&lt;/head&gt;
&lt;body&gt;
    &lt;div id="test" style="width:500px;height:400px; margin:20px auto;"&gt;&lt;/div&gt;
&lt;script&gt;
    $(window).load(function () {
        $.ajax({
            dataType: "json",
            url: 'ajax.php',
            success:function(data){         
                $("#test").html(data);
            }
        });
    });
&lt;/script&gt;
&lt;/body&gt;
&lt;/html&gt;      
</code></pre>

<p><strong>Ajax.php:</strong>   </p>

<pre><code>&lt;?php
require 'db.php';
$query="select lat,lng from locations order by id";
$result = pg_query($link, $query);
if (!$result) {
echo "An error occurred_xxx.\n";
}else {
$arr = pg_fetch_all($result);
echo json_encode($arr);
}  ?&gt;
</code></pre>