Receive paramter with cURL PHP using XMLHTTP JavaScript

My program is using a JS XMLHTTP request to a PHP file with cURL code to retrieve the contents of another page. I'm calling a PHP file in order to avoid a cross-origin-request error by the browser. I need to send my PHP file a JS variable, psswd, so it can use it when executing a cURL request.

I'm using the following JavaScript code to get the contents of another page:

var psswd = "test";
var xmlhttp;
if (window.XMLHttpRequest){ xmlhttp = new XMLHttpRequest(); }
else{ xmlhttp = new ActiveXObject("Microsoft.XMLHTTP"); }
xmlhttp.open("POST", "parsefeed.php?psswd=" + psswd, false);
xmlhttp.send();

My cURL PHP script where i need to use this variable is:

$options = array( 
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_FOLLOWLOCATION => true,
    CURLOPT_SSL_VERIFYHOST => false,
    CURLOPT_SSL_VERIFYPEER => false,
    CURLOPT_URL            => $url ,
    CURLOPT_SSLCERT        => $cert_file ,
    CURLOPT_SSLCERTPASSWD  => $< * VARIABLE GOES HERE * >,
);
curl_setopt_array($ch , $options); 
$output = curl_exec($ch);
echo $output;

I've tried using $_POST['psswd'] and checking if anything is even posted, but it doesn't seem to work. Any ideas how I can verify the variable is being passed?