Error performing actual time request with XMLHttpRequest

I'm having an error in my Real Time request via XMLHttpRequest, follow the javascript code:

function requisitar() {
    var base_url = window.location.origin;

    var xmlhttp;
    if (window.XMLHttpRequest)
    {
        xmlhttp = new XMLHttpRequest();
    } else
    {
        xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
    }
    xmlhttp.onreadystatechange = function ()
    {
        if (xmlhttp.readyState == 4 && xmlhttp.status == 200)
        {
           document.getElementById("solicitacao_mesas").innerHTML = xmlhttp.responseText;
        }
    }
    xmlhttp.open("GET", base_url + "/modulos/lista_solicitacao_mesas.php", true);
    xmlhttp.send();
}     
window.setInterval(requisitar, 1000);

Now follow my PHP:

header('Cache-Control: no-cache, no-store, must-revalidate');
header('Pragma: no-cache');
header('Expires: 0');
include_once($_SERVER['DOCUMENT_ROOT'] . '/conexao/conecta.php');

$read = new Read;
$read->ExeRead("ws_notificacao");
if ($read->getResult()) {
foreach ($read->getResult() as $mesa) {

    $read->ExeRead("ws_users", "where user_id = :id", "id={$mesa->user_id}");
    if ($read->getResult()) {
        $user = $read->getResult()[0];
    }

    if ($mesa->status == 0) {
        echo "<audio style=\"display:none;\" autoplay=\"autoplay\" controls=\"controls\">
                <source src=\"{$base}/images/alert.mp3\" type=\"audio/mp3\" />
                Seu navegador não suporta HTML5
            </audio>";
        $btn = "<a class=\"btn btn-success btn-md btn-flat aceitar\" data-id=\"{$mesa->notificacao_id}\">Aceitar</a>&nbsp;<a class=\"btn btn-danger btn-md btn-flat rejeitar\" data-id=\"{$mesa->notificacao_id}\">Rejeitar</a>";
    } else {
        $btn = "";
    }
    $data = date('d/m/Y', strtotime($mesa->data));
    $hora = date('H:i:s', strtotime($mesa->hora));
    echo "<tr><td>{$mesa->notificacao_id}</td><td>{$mesa->mesa_id}</td><td>{$user->user_name} {$user->user_lastname}</td><td>{$data}</td><td>{$hora}</td><td>{$btn}</td></tr>";
}}

The error that is returned:

<b>Parse error</b>:  syntax error, unexpected 'endif' (T_ENDIF) in <b>/app.artcomacucar.com.br/modulos/lista_solicitacao_mesas.php</b> on line <b>21</b><br />