client and server code

I am developing a web site using asp.net and c# as codebehind file in visual studio .net.
could you please tell me which is the client side code and which one is server side code.

all methods and events in de codebehind are serverside!

When you want to use clientside scripting, you can use Javascript.

also some times asp.net server controls create client-side codes for example validation controls that for security create both server and client-side codes for validation.