Lesson goal
The Document Object Model is the browser representation of the page. Traditional JavaScript directly selects and changes DOM elements. React gives us a cleaner method, but events such as click, input, submit, and keydown remain very important.
React connection: This topic appears directly in React components, props, state, event handlers, rendering lists, API calls, or project folder structure.
Explanation
Read the code slowly. Do not only copy it. Ask three questions: What data is stored? What operation is performed? What output is produced? This habit will help you understand React JSX (JavaScript XML), props, state updates, and component logic.
Interactive code practice
Edit the code and click Run Code. The runner is local and works after extracting the ZIP.
Try it yourself
Output will appear here.
Key points
| Point | Why it matters for React |
|---|---|
| Clean JavaScript | React components are mostly JavaScript functions. |
| Readable names | Good names make component code easier to maintain. |
| Small steps | React apps are built by combining small pieces. |
Practice task: Modify the example. Add your own data, print a different message, and intentionally make one mistake. Then fix it.
Check your understanding
How will this topic help when learning React?
It helps because React uses JavaScript to calculate values, pass data, handle events, render lists, and decide what should appear on the page.