Správa uživatelů PHP

<?php
/**
 * @author sczdavos
 * @site www.itnetwork.cz
 */

header('Content-type: text/html; charset=utf8');

$users = array();
foreach (explode("\n", file_get_contents('login.txt')) as $row)
{
    $users[] = explode(":", trim($row));
}

if (isset($_POST['del']))
{
    echo('Uživatelé: ');
    foreach ($_POST['del'] as $delIndex)
    {
        echo($users[$delIndex][0] . ',');
        unset($users[$delIndex]);
    }
    echo(' byli smazáni');
}

echo('<form method="post">
    <table>
        <tr>
            <th>&nbsp;</th><th>číslo</th><th>jméno</th><th>heslo</th>
        </tr>');

foreach ($users as $n => $user)
{
    echo('
        <tr>
            <td><input type="checkbox" name="del[]" value="' . $n . '"</td>
            <td>' . ($n + 1) .'</td>
            <td>' . $user[0] .'</td>
            <td>' . $user[1] .'</td>
        </tr>
        ');
}

echo('</table>
    <input type="submit" name="delete" />
</form>');