php 自定生成随机密码函数

function return_password () {

// set password length
$pw_length = 8;
// set ASCII range for random character generation
$low_ascii_bound = 50; // "2"
$upper_ascii_bound = 122; // "z"

// Exclude special characters and some confusing alphanumerics

排除一些特殊字符和字母数字混淆
// o,O,0,I,1,l etc
$notuse = array (58,59,60,61,62,63,64,73,79,91,92,93,94,95,96,108,111);

while ($i < $pw_length) {
mt_srand ((double)microtime() * 1000000);
// random limits within ASCII table
$randnum = mt_rand ($low_ascii_bound, $top_ascii_bound);
if (!in_array ($randnum, $notuse)) {
$password = $password . chr($randnum);
$i++;
}
}

return $password;
}