I think this is completely unnecessary.
I think this is completely unnecessary.
The reason why you don’t use spaces at the beginning and end is probably to avoid mistyping
How do you distinguish between full-width spaces and half-width spaces?
It is difficult to verify the number of spaces
Generally, spaces at the beginning and end will be filtered out.
When your service supports Mobile phone number login, you will know why
conflicts with UID. Generally, you can see some user information by entering the UID in the address bar. If the username is also all numeric, the system does not know whether it is the username or UID. Back-end logic processing is also relatively troublesome.
The above is why many website usernames do not allow numbers to begin with? Passwords are not allowed to start and end with spaces? Is this a technical reason? ? For more related content, please pay attention to the PHP Chinese website (www.php.cn)!