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