// callback handler called on success
request.done(function (response) {
    $('#add--response').html(response);
});

$count=0;
foreach ($_POST['URLS'] as $url) {

    if(!empty($url)){

            echo 'whatever';

            if (<here I download a file that takes a long time>)
            {
                echo '<div id="conversionSuccess">here is the progress bar for the download</div>';

            }
            else
            {
                echo 'Error!';
            }
            $count++;
            echo "count: ".$count."<br>";


        }
    }

$response = "";
$response .= $outputOne . "/";
$response .= $outputTwo . "/";
echo $reponse;

var output = reponse.split("/");