React JSX

Write HTML-like markup in JavaScript.

✍️ 3 exercises + code challenge in this lesson

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JSX lets you write HTML-like code in JavaScript. It is compiled into React.createElement() calls.

JSX rules

Return a single root element (wrap siblings in <>...</>, a Fragment).
Close every tag, including <img /> and <br />.
Use className instead of class, and htmlFor instead of for.
Put JavaScript expressions in curly braces: {2 + 2}, {user.name}.
Inline styles are objects: style={{ color: "red" }}.

Key Takeaways: React JSX

Mastering React JSX helps you write clean and reliable React code. Follow standard conventions, test edge cases, and keep logic simple. Try running the code example below and complete the exercises to build confidence.

React JSX Code Example

React

<div id="root"></div>
<script src="https://unpkg.com/react@18.3.1/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@18.3.1/umd/react-dom.development.js"></script>
<script src="https://unpkg.com/@babel/standalone@7.25.6/babel.min.js"></script>

<script type="text/babel">
const { useState, useEffect, useRef, useMemo, createContext, useContext } = React;
function App() {
  const name = "Sara";
  const lessons = 12;
  const avatar = "https://i.pravatar.cc/80?img=5";

  return (
    <>
      <img src={avatar} alt={name} style={{ borderRadius: "50%" }} />
      <h2 className="title">Welcome back, {name}!</h2>
      <p>You have finished {lessons} lessons ({Math.round(lessons / 20 * 100)}%).</p>
    </>
  );
}

ReactDOM.createRoot(document.getElementById("root")).render(<App />);
</script>

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React JSX Practice Exercises

Check what you learned in “React JSX”.

/ 3 solved

Fill in the blank

In JSX, the class attribute is written as…

<div ="card">Hi</div>

✓ Correct! Not quite. Try again.

Multiple choice

How do you insert a JavaScript expression in JSX?

With curly braces {} With $() With <% %> With quotes

✓ Correct! Not quite. Try again.

Code challenge

Render "Hello, Sara" using the name variable inside curly braces in an <h2>.

Write the code in the live editor. Your answer is checked automatically.

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React JSX

JSX rules

💡 Key Takeaways: React JSX

React JSX Code Example

React JSX Practice Exercises

Key Takeaways: React JSX