JSX (JavaScript XML) is an extension to JavaScript used in React to define the structure and content of components in a declarative manner. JSX allows you to write HTML-like code within your JavaScript code. Here's an example to illustrate JSX in React: 

import React from 'react';

const App = () => {
  const name = 'John';

  return (
    

      
Hello, {name}!

      
Welcome to React.

    

  );
};
In the above example, we have a functional component named `App`. It returns JSX code that represents the structure and content of the component's UI. The JSX code consists of HTML-like syntax and JavaScript expressions: - The `<div>` element is the root element of the component. - The `<h1>` element renders the greeting message with the value of the `name` variable interpolated using curly braces `{}`. - The `<p>` element displays a welcome message. The JSX code is transformed into regular JavaScript code using a transpiler like Babel. The transformed code would look like: 


import React from 'react';

const App = () => {
  const name = 'John';

  return React.createElement(
    'div',
    null,
    React.createElement('h1', null, 'Hello, ', name, '!'),
    React.createElement('p', null, 'Welcome to React.')
  );
};
The transpiled code uses the `React.createElement` function to create React elements that represent the components and their attributes. This transformation allows React to efficiently render and update the component tree based on the JSX representation. JSX in React provides a concise and readable way to define the structure and content of components, making the code more expressive and easier to understand. It combines the power of JavaScript with HTML-like syntax, allowing you to build dynamic and interactive UIs in a familiar and intuitive way. Here are a few key points about JSX and how it differs from HTML: 1. Embedding JavaScript Expressions: JSX allows you to embed JavaScript expressions within curly braces `{}`. This enables dynamic content rendering and the use of variables, functions, or any JavaScript expression directly within the JSX code. It provides a seamless integration of JavaScript logic and HTML-like structure. Example: 

const name = 'John';
const element = 
Hello, {name}
;
2. HTML-Like Syntax: JSX resembles HTML syntax, allowing you to define elements, attributes, and content in a familiar way. You can use tags such as `<div>`, `<h1>`, `<p>`, and include attributes like `className` (instead of `class`), `onClick`, etc. However, there are a few differences in attribute names and some special conventions (e.g., `className` instead of `class`) to avoid conflicts with JavaScript reserved keywords. Example: 

const element = <div classname="container">
  <h1>Welcome to React</h1>
  <p>React makes it easy to build interactive UIs!</p>
3. Components and Nesting: JSX allows you to define and nest components just like HTML elements. You can compose components together, pass properties to them, and nest them within other components, forming a hierarchical structure. Example: 

const Greeting = (props) => {
  return <h1>Hello, {props.name}!</h1>
};

const App = () => {
  return (
    <div>
      <greeting name="John">
      <greeting name="Jane">
    </greeting></greeting></div>
  );
};
4. Expressions and Conditionals: You can use JavaScript expressions and conditionals (such as `if` statements or ternary operators) within JSX to conditionally render elements or compute dynamic values. Example: 

const isLoggedIn = true;

const element = (
  

    {isLoggedIn ? <p>Welcome, user!</p> : <p>Please log in.</p>}
  

);
Conclusion Overall, JSX provides a convenient and expressive way to define the structure and behavior of components in React. It combines the power of JavaScript with HTML-like syntax, allowing developers to build dynamic and reusable UI components efficiently. While JSX resembles HTML, there are certain differences in syntax and conventions to be aware of when working with React.