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Top 50 JavaScript Interview Questions

The most frequently asked JavaScript interview questions for freshers and experienced developers.

1.What is the difference between var, let, and const?
2.Explain closures in JavaScript.
3.What is the Event Loop?
4.What is 'this' keyword in JavaScript?
5.Explain the difference between == and ===.

Q1.What is the difference between var, let, and const?

var is function-scoped and hoisted. let and const are block-scoped. const cannot be reassigned.

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Q2.Explain closures in JavaScript.

A closure is a function that remembers its outer variables and can access them even when called independently.

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Q3.What is the Event Loop?

The Event Loop is a mechanism that allows JavaScript to perform non-blocking I/O operations by offloading operations to the system kernel whenever possible.

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Q4.What is 'this' keyword in JavaScript?

'this' refers to the object that is executing the current function. Its value depends on how the function is called.

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Q5.Explain the difference between == and ===.

== performs type coercion before comparison, while === checks for both value and type equality.

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Top 50 JavaScript Interview Questions

Table of Contents

Q1.What is the difference between var, let, and const?

Q2.Explain closures in JavaScript.

Q3.What is the Event Loop?

Q4.What is 'this' keyword in JavaScript?

Q5.Explain the difference between == and ===.

Master Interviews
Anywhere, Anytime

Top 50 JavaScript Interview Questions

Table of Contents

Q1.What is the difference between var, let, and const?

Q2.Explain closures in JavaScript.

Q3.What is the Event Loop?

Q4.What is 'this' keyword in JavaScript?

Q5.Explain the difference between == and ===.

Table of Contents

Q1.What is the difference between var, let, and const?

Q2.Explain closures in JavaScript.

Q3.What is the Event Loop?

Q4.What is 'this' keyword in JavaScript?

Q5.Explain the difference between == and ===.

Master Interviews Anywhere, Anytime

Table of Contents

Q1.What is the difference between var, let, and const?

Q2.Explain closures in JavaScript.

Q3.What is the Event Loop?

Q4.What is 'this' keyword in JavaScript?

Q5.Explain the difference between == and ===.

Master Interviews
Anywhere, Anytime