<?php
//随机生成4位数字和字母混合的字符串
$pattern
=
'1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLOMNOPQRSTUVWXYZ'
;
for
(
$i
= 0;
< 4;
++) {
$code
.=
{mt_rand(0, 61)};
}
?>