$code = I('post.code');
if(check_verify($code)==false){
$this->error('验证码错误!');
}else{
$ye = $u->add($data);
if($ye) {
$this->success('注册成功！', 'login');
}else{
$this->error('注册失败！',1);
}

}
check_verify放在common/common/function