The username must be alphanumeric and contains 4 to 30 characters.kuai

The username must be alphanumeric and contains 4 to 30 characters.kuai
The username must be alphanumeric and contains 4 to 30 characters.
kuai

The username must be alphanumeric and contains 4 to 30 characters.kuai
用户名为字母或数字,包含4至30个以内的字符.

用户名必须是4－30位的字母或数字