在电子邮件地址中@符号之前的名称;
例句:
Userid-The number that is assigned to you when you register.
介绍用户码 – 你登记时所分配给你的号码.
Attempting to connect an invalid userid or password results in memory corruption or an Assert failure.
使用错误的用户名或者密码导致内存出错或者断言失败.
We must be unique is the combination of userid and domain.
用户标识符与域名加在一起的组合应该是唯一的.