Kliensoldal

Kliensoldal, Hungarian for client side, refers to the portion of a software system that executes on the user's device rather than on a remote server. In web development, the kliensoldal runs in the web browser and is primarily responsible for presentation and user interaction, while server-side code handles data storage, business logic, and server resources.

The kliensoldal uses HTML for structure, CSS for styling, and JavaScript for behavior. It can manipulate the Document Object Model (DOM), respond to user input, perform form validation, render dynamic content, and store data locally via APIs such as localStorage or IndexedDB. With progressive web apps, it can also support offline operation and caching through service workers.

Architectures vary in how much work is done on the client. Client-side rendering (CSR) builds the UI in the browser after loading scripts; server-side rendering (SSR) sends pre-rendered HTML from the server. Many modern applications use a mix, with initial HTML delivered by the server and subsequent UI rendered by the kliensoldal using frameworks such as React, Vue, or Angular.

Security and performance are important considerations. Since code runs on the client, it can be inspected and manipulated by users; sensitive operations should be performed on the server. Client-side validation improves responsiveness but should be complemented by server validation. Performance depends on device capability and network; optimizing assets and using lazy loading help.

In a typical architecture, the kliensoldal provides the interactive experience and presentation, while the server provides data, authentication, and services. The concept is central to web and app development, influencing design, usability, and deployment strategies.