What is client-side, server-side?

If a webpage content can be customised or used to complete an activity, interaction is either client-side or server-side.

client-side

Client-side scripting enables interaction within a webpage. The code required to process user-input is downloaded and compiled by the browser or plug-in. An example of a client-side interaction is a rollover (typically triggered when choosing a navigation option).

Client-side scripting languages include JavaScript.

server-side

With server-side scripting, completing an activity involves sending information to another computer (server) across the internet. The server then runs a program that process the information and returns the results, typically a webpage.

Search engines use server-side processing. When a keyword is sent, a program on a server matches the word or phrase entered against an index of website content. (To complete the same search as a client-side process would require the browser to download the entire search engine program and index.)

Server-side scripting languages include ASP and PHP.