Client-side and server-side are two terms that are commonly used in the context of web applications. The client-side refers to the part of the application that runs on the user’s computer or device, typically in a web browser. The server side, on the other hand, refers to the part of the application that runs on a remote server, often called a backend server.

Client Side: The client-side typically consists of HTML, CSS, and JavaScript. HTML provides the structure of the web page, CSS provides the layout and styling, and JavaScript provides interactivity and dynamic behavior. When you visit a website, your browser downloads these files to your computer and renders the web page based on the instructions in these files.

Server Side: Server-side code is executed on the server itself, and is typically used to build APIs or database-driven web applications. The most common server-side programming languages are PHP, Python, Ruby, Java, and Node.js.

When you submit a form on a web page or perform any other action that requires data to be saved to a server or database, the client-side code sends a request to the server, and the server processes the request and sends a response to the client.

In summary, client-side programming is focused on building the user interface and handling user interactions, while server-side programming is focused on processing requests and responding with the appropriate data or result.