ReactJS vs JavaScript: Key Differences and Examples

ReactJS vs Plain JavaScript

What is the Difference?

Plain JavaScript (often called vanilla JavaScript) gives you direct control over the DOM. React adds a layer on top that manages the DOM for you, based on your data.

React is written in JavaScript. Learning React does not replace JavaScript it builds on it.

Comparison

Example: The Same Task Both Ways

Plain JavaScript

<p id="course-name">Loading...</p>
<script>
  const course = "Full Stack Development";
  document.getElementById("course-name").innerText = course;
</script>

React

function CourseName() {
  const course = "Full Stack Development";
  return <p>{course}</p>;
}

export default CourseName;

How It Works

In the plain JavaScript version, you find the element and set its text. In the React version, you write the variable directly inside the UI using curly braces, and React puts it on screen. With one value the difference is small. With twenty values that change in response to user actions, the difference is enormous.

Key Takeaways

• JavaScript is a language; React is a library written in that language.
• React replaces manual DOM updates with data-driven rendering.
• Strong JavaScript skills make React much easier to learn.
• React requires a build setup; plain JavaScript does not.