JavaScript MCQs with answers Page - 153

Here, you will find a collection of MCQ questions on JavaScript. Go through these questions to enhance your preparation for upcoming examinations and interviews.

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Q. What is the default scope of variables declared with var?

  • (A) Block
  • (B) Function
  • (C) Global
  • (D) Module

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Q. Which keyword prevents object modification?

  • (A) const
  • (B) Object.seal()
  • (C) Object.freeze()
  • (D) Object.prevent()

A

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Q. What is the result?

Code: 
let a = [1,2,3];
a.length = 0;
console.log(a);
  • (A) []
  • (B) [1,2,3]
  • (C) undefined
  • (D) null

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Q. Which keyword is used to handle errors?

  • (A) handle
  • (B) try
  • (C) check
  • (D) error

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Q. What is the output?

Code: 
let x = [1,2,3];
console.log(x instanceof Array);
  • (A) true
  • (B) false
  • (C) undefined
  • (D) SyntaxError

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Q. What does the spread operator (...) do?

  • (A) Deletes properties
  • (B) Merges arrays or objects
  • (C) Freezes variables
  • (D) Compiles code

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Q. What will this output?

Code: 
let name = 'John';
console.log(`Hello ${name}`);
  • (A) Hello ${name}
  • (B) Hello name
  • (C) Hello John
  • (D) undefined

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Q. Which object method is used to get object keys?

  • (A) Object.getKeys()
  • (B) Object.keys()
  • (C) Object.values()
  • (D) Object.entries()

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Q. What will be the output of the following code?

Code: 
console.log(typeof null);
  • (A) object
  • (B) null
  • (C) undefined
  • (D) number

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Q. What does the following expression evaluate to?

Code: 
console.log(1 + '2' + 3);
  • (A) 6
  • (B) 123
  • (C) 33
  • (D) 15

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