if (isset($_SERVER['HTTP_ORIGIN'])) {
    header("Access-Control-Allow-Origin: {$_SERVER['HTTP_ORIGIN']}");
    header('Access-Control-Allow-Credentials: true');
    header('Access-Control-Max-Age: 86400');    // cache for 1 day
}
// Access-Control headers are received during OPTIONS requests
if ($_SERVER['REQUEST_METHOD'] == 'OPTIONS') {

    if (isset($_SERVER['HTTP_ACCESS_CONTROL_REQUEST_METHOD']))
        header("Access-Control-Allow-Methods: GET, POST, OPTIONS");

    if (isset($_SERVER['HTTP_ACCESS_CONTROL_REQUEST_HEADERS']))
        header("Access-Control-Allow-Headers:        {$_SERVER['HTTP_ACCESS_CONTROL_REQUEST_HEADERS']}");

    exit(0);
}
$dbhost='localhost';
$user='root';
$password='';
$dbName='testdatabase';
$con = mysqli_connect("$dbhost" , "$user" , "$password");

mysqli_select_db($con,"testdatabase");

$postdata = file_get_contents("php://input");

if (isset($postdata)) {
    $request = json_decode($postdata);
    //$username = $request->username;

    $username  = $request->username;


    if ($username != "") {
        echo "Server returns: " . $username;
        // $sql = mysqli_query($con, "INSERT INTO doctortable (Name, Username, Password)
        // VALUES ('TEST', 'TEST', 'TEST')");
    }
    else {

        echo "Empty username parameter!";
    }
}
else {
    echo "Not called properly with username parameter!";
}