Apart from a normal interpretation of function (as in other languages like C or pascal), functions are also used for the following:
It may be pertinent to point out that writing on the client is forbidden, due to security issues. However, it is possible that small bits of information may be stored in a controlled manner, on the client side. This is possible in the form of a Cookie.
Cookies are not complete without their role in the server side. They are discussed in more detail on the server side in this book.
A Cookie is a piece of information stored in the client's machine. It is used in several contexts but the main reason is ...