What is server-side rendering (SSR) and what is hydration in React?

What is server-side rendering (SSR) and what is hydration in React?

• A. SSR renders HTML on the server for faster initial load.
• B. Hydration attaches React event handlers to the server-rendered HTML on the client.
• C. Hydration attaches CSS styles to HTML after rendering.
• D. SSR makes the server deliver only JSON data.

Answer: (B)

Hydration is the process where the JavaScript running in the browser takes the HTML markup produced by the server and connects it to React’s event system and internal state, making the page interactive. With server-side rendering, the server sends fully formed HTML so users see content quickly, while the client loads React and hydrates that markup by attaching event listeners and preparing the DOM to be managed by React without re-rendering the entire UI. The description that hydration attaches React event handlers to the server-rendered HTML on the client captures this interaction step precisely. The other statements don’t describe hydration accurately—they either focus only on server-rendered HTML versus JSON delivery or mention CSS, which isn’t what hydration does.

Hydration is the process where the JavaScript running in the browser takes the HTML markup produced by the server and connects it to React’s event system and internal state, making the page interactive. With server-side rendering, the server sends fully formed HTML so users see content quickly, while the client loads React and hydrates that markup by attaching event listeners and preparing the DOM to be managed by React without re-rendering the entire UI. The description that hydration attaches React event handlers to the server-rendered HTML on the client captures this interaction step precisely. The other statements don’t describe hydration accurately—they either focus only on server-rendered HTML versus JSON delivery or mention CSS, which isn’t what hydration does.