Question

In my project I have to make a subdomain, i.e

if the user name is XXX when he register, a sub domain will be created like XXX.example.com

how to do it?

I will use php for scripting.

Answer 1

I found a script that seems to do exactly that, create a subdomain on your server on demand.
It probably needs a little bit of tweaking for it to work on your particular control panel, but the review are quite positive as far as I can tell.

Link

Have you considered using htaccess and url rewriting?
Found this code that may help you:

# Rewrite <subdomain>.example.com/<path> to example.com/<subdomain>/<path>
#
# Skip rewrite if no hostname or if subdomain is www
RewriteCond %{HTTP_HOST} .
RewriteCond %{HTTP_HOST} !^www\. [NC]
# Extract (required) subdomain (%1), and first path element (%3), discard port number if present (%2)
RewriteCond %{HTTP_HOST}<>%{REQUEST_URI} ^([^.]+)\.example\.com(:80)?<>/([^/]*) [NC]
# Rewrite only when subdomain not equal to first path element (prevents mod_rewrite recursion)
RewriteCond %1<>%3 !^(.*)<>\1$ [NC]
# Rewrite to /subdomain/path
RewriteRule ^(.*) /%1/$1 [L]

Source (Post #6)