1.
I'm creating a website, where a user signs up, and they get a homepage.

Right now, the format is
domain.com\homepage.php?user=username
but some sites have things like
domain.com\username

I was just wondering how this is done. I'd guess that a new folder is created for each user, am I correct, or can this be done through some code.

Are there any advantages / disadvantages to creating folders for everyone?
Aside from the files taking space, which wouldn't be much because I could just include the php code from elsewhere.

2.
Also, I'm allowing users to do their own CSS code, should I store it in a database, or create an external file for each one. I just thought there might be some security flaws in storing it in the database(some sort of injection).

You don't actually create folders, you merely give the impression of folders using some .htaccess rewrite trickery, providing you are hosted on Apache of course.

For CSS code I tend to go with a real physical file, nothing to do with security though, more to do with speed and browser caching.

Stylesheets stored in a database have to be either included in the page or created "on the fly" at each page access. By creating them each time they are always "new" so will be "re-cached" each time.
However, having said that, if the users only have the one page, an in-page stylesheet isn't really going to be much of an issue.

And because you write the CSS into the page the security issue is minimal, just make sure you "break" anything that looks like it could be javascript.
Replacing "<" & ">" with nothing or the equivalent HTML entity will be enough.

Originally Posted by chrishirst

You don't actually create folders, you merely give the impression of folders using some .htaccess rewrite trickery, providing you are hosted on Apache of course.

For CSS code I tend to go with a real physical file, nothing to do with security though, more to do with speed and browser caching.

Stylesheets stored in a database have to be either included in the page or created "on the fly" at each page access. By creating them each time they are always "new" so will be "re-cached" each time.
However, having said that, if the users only have the one page, an in-page stylesheet isn't really going to be much of an issue.

And because you write the CSS into the page the security issue is minimal, just make sure you "break" anything that looks like it could be javascript.
Replacing "<" & ">" with nothing or the equivalent HTML entity will be enough.

Cool, do you know any good tutorials for .htaccess? I can't find any and I can't get it to do what I want
(type domain.com/register but show domain.com/register.php)

Not a tutorial as such, but -> http://www.highrankings.com/forum/in...p?showforum=61 has probably got more examples of .htaccess rewrites than most places.