…supports interaction within a webpage
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).
information is sent to a server to be processed
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.)
Macromedia Flash application architecture enables a third type of scripting/interaction. Flash can store and process information both client-side and server-side.
An example of this interaction is a Flash-based checkout process. Information the user enters (such as delivery and billing addresses, credit card details, etc.) can be stored and validated client-side. Once the required information has been completed a connection is established to the server and the order sent for processing.
How the user connects to the internet affects both forms of interaction. For client-side scripting, the connection type affects the time it takes program code to be downloaded. For server-side processing, it affects the time taken for information to be sent to the server and the response downloaded.