php random password generator

gistfile1.php

// string of random a-z, A-Z, 0-9

function generatePassword($length = 8) { 
    $chars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789'; 
    $count = mb_strlen($chars); 
 
    for ($i = 0, $result = ''; $i < $length; $i++) { 
        $index = rand(0, $count - 1); 
        $result .= mb_substr($chars, $index, 1); 
    } 
 
    return $result; 
}