How to dynamically create subdomains

Question

I want to dynamically create new sub domains on my website. i mean if you have example.com then you dynamically create sub.example.com .

i looked on google and there

Answer 1

You can't do this unless you have permission to alter the DNS server for your domain.

Answer 2

You need to setup a wildcard subdomain. Basically, anything.mysite.com will resolve to mysite.com. At that point it's up to your code to kick in and serve up the proper content depending on what subdomain the user is looking at.

http://www.google.lk/search?q=wildcard+subdomain