随机密码

<?
function GetSID ($nSize=24) {
mt_srand ((double) microtime() * 1000000);
for ($i=1; $i<=$nSize; $i++) {
$nRandom = mt_rand(1,30);
if ($nRandom <= 10) {
$sessionID .= chr(mt_rand(65,90));
} else {
$sessionID .= chr(mt_rand(97,122));
}
}
return $sessionID;
}
echo GetSID(16);
?>