Non esegue il download del file

[ninja72]

<formaction="scarica.php"method="POST">
        <inputtype="date"name="rCerca"id="rCerca"value="">
        <inputtype="date"name="rCercaAl"id="rCercaAl"value="">
        <inputtype="submit"value="download"id="download">
    </form>

    <script>
lettoday=newDate().toISOString().slice(0, 10)
letdal=document.getElementById("rCerca");
letal=document.getElementById("rCercaAl");

dal.setAttribute("value", today);
al.setAttribute("value", today);
</script>

<?php

$dal = date_create($_POST['rCerca']);
$dal = date_format($dal, 'd-m-Y');
$al = date_create($_POST['rCercaAl']);
$al = date_format($al, 'd-m-Y');
$file =  "./csv/report_segnalazioni_" . str_replace("-", "", $dal) . "_" . str_replace("-", "", $al) . ".csv";
if (!file_exists($file)) {
    // se non esiste stampo un errore
    echo "Il file : " . basename($file) . " non esiste!(redirect in 3sec.)";
    header("refresh:3; index.html");
    exit;
} else {
    $filedimension = filesize($file);
    header("Content-type: text/csv; charset=UTF-8");
    header("Content-Disposition: attachment; filename=" . basename($file));
    header("Content-Description: Download file");
    header("Content-Length: $filedimension");
    readfile($file);
}