Is it possible to make an “add to favorites” feature using cookies?

Question

I want to make a function using php, where guests can add posts to their favorites (so no signup is needed). I tried using MySQL but I got to a dead end because I couldn't find a way to determine a unique device. Some people have told me that I can do the same thing using cookies, can anyone tell me how?

Answer 1

1. User clicks "favorite this post" button/link
2. Using PHP you set the cookie containing favorited post id, along with the already favorites id's that might have been there.
3. On the "your favorite posts" page you retrieve the cookie and query the database for the id's.