function generatePassword ($length = 8) {
$password = "";
$possible = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_-$!?][";
$i = 0;
// add random characters to $password until $length is reached
while ($i < $length) {
// pick a random character from the possible ones
$char = substr($possible, mt_rand(0, strlen($possible)-1), 1);
// we don't want this character if it's already in the password
if (!strstr($password, $char)) {
$password .= $char;
$i++;
}
}
return $password;
}