React Forms & Events Interview Questions 2026

📖 Introduction

This comprehensive guide focuses on React Forms & Events interview questions covering form handling and event management. Whether you're preparing for your first React.js interview or looking to refresh your knowledge, this resource provides detailed answers with code examples to help you succeed.

What you'll learn:

Controlled Components: Managing form state with React
Uncontrolled Components: Using refs for form inputs
Form Validation: Implementing validation logic
Event Handling: Understanding synthetic events
Form Submission: Handling form submissions properly
Multiple Inputs: Managing complex forms with multiple fields

Perfect for:

Developers preparing for React.js interviews focusing on forms
Frontend engineers looking to master form handling in React
Teams conducting React technical assessments
Anyone learning React and seeking comprehensive interview preparation

Keywords: React Forms & Events interview questions, React JS interview questions, React.js interview questions, interview questions on react js Key Features:

5+ React Forms & Events interview questions with detailed explanations
Code examples for every concept
Updated for 2026 with latest React features
Covers all difficulty levels from beginner to advanced
Practical answers you can use in real interviews

React Forms & Events

How are forms handled in React compared to plain HTML?

In plain HTML, the browser's DOM manages form data. In React, form inputs are usually controlled components:

The form values live in state.
Each keystroke triggers an onChange handler to update state.
This makes the data predictable and easy to validate before submission.

function MyForm() {
  const [name, setName] = React.useState("")

  const handleSubmit = (e) => {
    e.preventDefault()
    alert("Submitted: " + name)
  }

  return (
    <form onSubmit={handleSubmit}>
      <input type="text" value={name} onChange={(e) => setName(e.target.value)} />
      <button type="submit">Submit</button>
    </form>
  )
}

In this example, the input is fully controlled by React through value and onChange.

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How do you prevent the default form submission behavior in React?
By using event.preventDefault() inside the form's onSubmit handler.
```
const handleSubmit = (e) => {
  e.preventDefault()
  console.log("Form submitted!")
}
```
In this example, the page is stopped from reloading and lets React control what happens on submit.
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What is event bubbling and how can you stop it in React?
- Event Bubbling: When an event triggered on a child element propagates upward to its parent elements.
- In React, you can stop it using event.stopPropagation().
```
const handleClick = (e) => {
  e.stopPropagation()
  console.log("Child clicked, but won't bubble up.")
}
```
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How do you handle multiple input fields in a single form in React?
By using a single state object and updating it dynamically with name and value.
```
const [formData, setFormData] = useState({ name: "", email: "" })

const handleChange = (e) => {
  setFormData({ ...formData, [e.target.name]: e.target.value })
}
```
This way, one handler can manage multiple inputs.
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How do you reset form fields after submission in React?
In React, form inputs are usually controlled components, meaning their values are stored in state. To reset a form, you simply reset the state that controls the inputs:
```
const [formData, setFormData] = useState({ name: "", email: "" })

const handleSubmit = (e) => {
  e.preventDefault()
  console.log(formData)
  // Reset form fields
  setFormData({ name: "", email: "" })
}
```
In this example:
- setFormData({ name: "", email: "" }) resets all input fields to their initial values.
- This triggers a re-render, updating the UI with empty inputs.
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