使用AJAX生成Dwolla访问令牌，而不是重定向到他们的网页

查看Dwolla的API文档并在我的站点上尝试oauth.php示例代码(下面显示的代码)，我不清楚是否可以在不重定向到Dwolla页面的情况下生成访问令牌。

从UI/UX的角度来看，从我的网站重定向到他们的网站再到我的网站真的很糟糕，比Paypal提供的蹩脚界面好不到哪里去。

有人知道如何使用AJAX生成Dwolla访问令牌吗?

<?php
// Include the Dwolla REST Client
require '../lib/dwolla.php';
// Include any required keys
require '_keys.php';
// OAuth parameters
$redirectUri = 'http://localhost:8888/oauth.php'; // Point back to this file/URL
$permissions = array("Send", "Transactions", "Balance", "Request", "Contacts",   "AccountInfoFull", "Funding");
// Instantiate a new Dwolla REST Client
$Dwolla = new DwollaRestClient($apiKey, $apiSecret, $redirectUri, $permissions);
/**
 * STEP 1: 
 *   Create an authentication URL
 *   that the user will be redirected to
 **/
if(!isset($_GET['code']) && !isset($_GET['error'])) {
$authUrl = $Dwolla->getAuthUrl();
header("Location: {$authUrl}");
}
/**
 * STEP 2:
 *   Exchange the temporary code given
 *   to us in the querystring, for
 *   a never-expiring OAuth access token
 **/
 if(isset($_GET['error'])) {
echo "There was an error. Dwolla said: {$_GET['error_description']}";
}
else if(isset($_GET['code'])) {
$code = $_GET['code'];
$token = $Dwolla->requestToken($code);
if(!$token) { $Dwolla->getError(); } // Check for errors
else {
    session_start();
    $_SESSION['token'] = $token;
    echo "Your access token is: {$token}";
} // Print the access token
}