Display Mysql Data in Cordova Using PHP and JSON - php

Question

I need to know what can done to display data from mysql database in cordova app.
I made a php file placed it on the server.
then i made the html with json code to fetch data from mysql database.
The data from mysql database should be displayed in the div with id="demo".
I have done this till now.
My Php file looks like this:
<?php
header("Content-Type: application/json; charset=UTF-8");
$obj = json_decode($_GET["x"], false);
include "../../webConfig/web.config.php";
$conn = connect();
$q = $conn->query("SELECT name FROM 'online_' ORDER BY DESC");
$rows=$conn->query($cb);
$rows=$conn->query($cb);
foreach($rows as $row){
echo $row["ID"];
echo $row["first_name"];
echo $row["middle_name"];
echo $row["last_name"];
}
echo json_encode($rows);
?>
My HTML file Looks like this.
<div data-role="content">
<div class="container-fluid">
Online Application
<p id="demo">
.....
</p>
<script>
var obj, dbParam, xmlhttp;
obj = { "table":"online", "limit":10 };
dbParam = JSON.stringify(obj);
xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
document.getElementById("demo").innerHTML = this.responseText;
}
};
xmlhttp.open("GET", "http://localhost/admin/notify/test.php?x=" + dbParam, true);
xmlhttp.send();
</script>
</div>
</div>
I have been trying to do this using json But my html file dosen't show anything apart from those dots.
I tried placing the php file on the web server as well, but still it did not show anyhing.