Is it alright to enable space in username? Is there any particular reason one can't enable users to put spaces in their usernames?

in what & for what?

I cannot find any logical explanation for restricting usage of spaces in usernames. Well, maybe if you store your data in plain text files and the space is fields delimiter.

Originally Posted by chrishirst

in what & for what?

Anything.

Ok, nothing particular in mind then.

the main reason spaces are not usually allowed in usernames or passwords is because a space is a delimiter in HTML and HTTP.
So an unencoded string using a space would "break" HTTP POST & GET transfers

Hold on, how'd it break post transfers?

because a space is a delimiter. That's why spaces in URIs become %20

A POST is the same, the text stream ends at the first space.

So what problems would that pose in normal use?

What use would cause the problems?

So what problems would that pose in normal use

Probably none at all.

What use would cause the problems?

Try sending a AJAX request with an unencoded space in the data
See what happens when you miss the quotes off for a form element attribute value when the data has a space in it.


other points;
email addresses cannot include a space.
subdomains and hostnames cannot have spaces in them. So if the system is setting up either of the above, spaces MUST not be allowed.

provided you are aware of the potential problems it can create and you take all steps to prevent them happening, it may never be a problem. But because there are many things that can go awry, it's simply safer not to allow spaces.

Ah yes, as for Ajax there's a javascript cure to encode

However I see your point now.

I just finished a script that makes an ajax call with text from a form text, writes it to a database and does some image manipulation using the text. I had to encode and unencode in a "loop", it was a real brain pain. But yes it does enhance a site to allow spaces and other special characters. Good-Luck!