Cookies! Yummy for your tummy.
That was fun but here is a real answer. You probably want to store information in a cookie. This is a good way to pass information from one part of your web application to another. It is a common technique so all platforms support it well.
Remember cookies are public so don't put any information that can be hacked. You should hash and or encrypt the value in a cookie. You can also generate random information -- this is best. For example, when a user logs in generate a random number and store that number and the user ID in a table then pass the random number as the cookie. In this way only your DB has the information and you can't hack the cookie (by adding one for example.)
