POST data to a different domain form without leaving current domain - php

Question

I am currently working on a project which requires me to POST data to an form belonging to a different domain. This does work but I don't want the user to see the data posted to the different domain as it just shows a success / error message (on page B).
What I want to do is have the data POST but the page not change. I have read that AJAX can be used to do this but only if the pages belong to the same domain. windows.location.replaced() looked promising but this only worked if I had access to the external form.
Current implementation:
User enters data on page A > POST data to page B, page B loads
Want I would like to implement:
User enters data on Page A > POST data to page B, page A remains displayed

Answer 1

Make use of cURL to do this.
Page1.php
$url='http://www.domain.com/page2.php';
$params='username=jim&pass=jim321';
$ch = curl_init($url);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $params);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
echo $result = curl_exec($ch); // This outputs the response in your same page i.e. Page1.php
curl_close($ch);

Answer 2

try using curl something like this
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL,"http://www.otherdoamin.com/page.php");
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS,"post1=val1&post2=val2&post3=val3");
// get server response ...
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$server_output = curl_exec ($ch);
curl_close ($ch);