<?php
$longest = "";
$lkey = "";
$data = "";
foreach ($_SERVER as $key => $value) {
    $safekey = htmlentities($key);
    $safevalue = htmlentities($value);
    $length = strlen($safevalue);
    if ($length > strlen($longest)) {
        $longest = $safevalue;
        $lkey = $safekey;
    }
    $data .= "$safekey = $length<br />";
}
?>
<p><?= $data ?></p>
<p>Longest value = <?= "$lkey:$longest" ?></p>
