JavaScript MCQ Questions with answers and solutions Page 149

Q. Which DOM method selects an element by its ID?

(A) document.getElementById()
(B) document.querySelectorAll()
(C) document.getElementByClass()
(D) document.findById()

💬 Discuss

✅ Correct Answer: (A) document.getElementById()

Explanation: getElementById returns a reference to the element with specified ID.

Published by Mr. Dubey ⭐ 111.42K Points at 11-Jun-2025 07:20 am in JavaScript

Q. Which DOM method returns the first element that matches a selector?

(A) querySelector()
(B) querySelectorAll()
(C) getElementById()
(D) getElementsByTagName()

💬 Discuss

✅ Correct Answer: (A) querySelector()

Explanation: querySelector returns the first element matching a CSS selector.

Published by Mr. Dubey ⭐ 111.42K Points at 11-Jun-2025 07:20 am in JavaScript

Q. Which object is used to manipulate the HTML document?

(A) document
(B) window
(C) location
(D) navigator

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✅ Correct Answer: (A) document

Explanation: The document object represents the HTML DOM and allows manipulation.

Published by Mr. Dubey ⭐ 111.42K Points at 11-Jun-2025 07:20 am in JavaScript

Q. What does the window object represent?

(A) The browser window
(B) The HTML page
(C) The document object
(D) The JavaScript engine

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✅ Correct Answer: (A) The browser window

Explanation: The window object represents the browser's window containing a DOM document.

Published by Mr. Dubey ⭐ 111.42K Points at 11-Jun-2025 07:20 am in JavaScript

Q. Which method can be used to change the content of an HTML element?

(A) innerHTML
(B) setAttribute
(C) value
(D) classList

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✅ Correct Answer: (A) innerHTML

Explanation: innerHTML allows you to get or set the HTML content of an element.

Published by Mr. Dubey ⭐ 111.42K Points at 11-Jun-2025 07:20 am in JavaScript

Q. Which method adds a new class to an element?

(A) classList.add()
(B) className.append()
(C) setClass()
(D) addClass()

💬 Discuss

✅ Correct Answer: (A) classList.add()

Explanation: classList.add() adds one or more classes to an element.

Published by Mr. Dubey ⭐ 111.42K Points at 11-Jun-2025 07:20 am in JavaScript

Q. Which method creates a new DOM element?

(A) document.createElement()
(B) document.newElement()
(C) element.create()
(D) create()

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✅ Correct Answer: (A) document.createElement()

Explanation: document.createElement() creates an HTML element dynamically in JavaScript.

Published by Mr. Dubey ⭐ 111.42K Points at 11-Jun-2025 07:20 am in JavaScript

Q. Which of the following is a correct way to declare a variable in JavaScript?

(A) var myVar;
(B) int myVar;
(C) let: myVar;
(D) declare myVar;

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✅ Correct Answer: (A) var myVar;

Explanation: The correct syntax to declare a variable is using var, let, or const. 'var myVar;' is correct.

Published by Chandani ⭐ 10.97K Points at 14-Jun-2025 07:38 am in JavaScript

Q. What will be the output of: console.log(typeof null);

(A) null
(B) undefined
(C) object
(D) boolean

💬 Discuss

✅ Correct Answer: (C) object

Explanation: In JavaScript, typeof null returns 'object' due to a legacy bug.

Published by Chandani ⭐ 10.97K Points at 14-Jun-2025 07:38 am in JavaScript

Q. Which of the following methods converts JSON data to a JavaScript object?

(A) JSON.parse()
(B) JSON.stringify()
(C) JSON.toObject()
(D) JSON.convert()

💬 Discuss

✅ Correct Answer: (A) JSON.parse()

Explanation: JSON.parse() is used to parse JSON strings and convert them into JavaScript objects.

Published by Chandani ⭐ 10.97K Points at 14-Jun-2025 07:38 am in JavaScript

JavaScript MCQs with answers Page - 149

Q. Which DOM method selects an element by its ID?

Q. Which DOM method returns the first element that matches a selector?

Q. Which object is used to manipulate the HTML document?

Q. What does the window object represent?

Q. Which method can be used to change the content of an HTML element?

Q. Which method adds a new class to an element?

Q. Which method creates a new DOM element?

Q. Which of the following is a correct way to declare a variable in JavaScript?

Q. What will be the output of: console.log(typeof null);

Q. Which of the following methods converts JSON data to a JavaScript object?

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