CODE EXAMPLE FOR PHP

php random characters

function random_chars($length = 12)
{
    $chars      = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!@#$%^&*()_?,.";
    $rand_chars = substr( str_shuffle( $chars ), 0, $length );
    return $rand_chars;
}