A simple page can be coded using HTML but it requires a command to run this page on the internet. The coding of command is written either in client side, or in server side or in both scripts. Usually a user interface program is scripted in the client side scripting where the user action is essential like button clicks, performing client oriented task etc. The client side coding is also used for creating dynamic web pages, which contents change frequently. Client-side script executes locally in the browser, which provides the user with a lively and responsive interface.
Though client side coded program runs on user’s local computer but it send and receive the data over local area network. Remember that if a program that runs on a user’s local computer without sending and receiving data over a network are not considered client-side scripting.
When any command or request is sent to the web server, the server sent the necessary file to the user’s server on which they reside. The user's web browser executes the script then displays the document with visible output from the script.