Check if same User visited web site!?! How?

Question

How can I check if User which came to my web site, is same User which came half hour before?

Answer 1

What do u mean from the user ? Is the user logs in to your website or just lands on your web site?

1.you can get the ipAddress of the user but no guarantee. 2.Using cookies. How long you want to do the same process ? (Same user which came half hour before) so the expiration date of the cookie is important.