Generate strong passwords with PHP

generator.php

<?php 

$symbols = str_split('!$%@#');
$chars   = str_split('abcdefghijklmnopqrstuvwxyz0123456789');
$pwlen   = isset($_POST['len']) ? (int) $_POST['len'] : 64;
$pwlen   = $pwlen > 1024 ? 1024 : $pwlen; // Max length: 1024
$useSyms = isset($_POST['sym']) && $_POST['sym'] === '0' ? false : true;
$passArr = array();

function getRand() {
    return hexdec(bin2hex(openssl_random_pseudo_bytes(1)));
}

function randFromArr($arr) {
    do {
        $x = getRand();
    } while ($x >= count($arr));

    return $arr[$x];
}

function randBelowLimit($limit) {
    do {
        $x = getRand();
    } while ($x >= $limit);

    return $x;
}

for ($i = 0; $i < $pwlen; $i++) {
    if (getRand() % 2 === 0) {
        $passArr[$i] = ucfirst(randFromArr($chars));
    } else {
        $passArr[$i] = randFromArr($chars);
    }
}

if ($useSyms) {
    $symlen = randBelowLimit($pwlen / 2);
    for ($i = 0; $i < $symlen; $i++) {
        $passArr[randBelowLimit($pwlen) - 1] = randFromArr($symbols);
    }
}

echo implode('', $passArr);