JavaScript Interview Questions, Answers for Freshers and Experienced asked in various Company Job Interviews

JavaScript Interview Questions

Questions Answers Views Company eMail

How do you extend classes Code snippet: const circle = { radius: 20, diameter() { return this.radius * 2; }, perimeter: () => 2 * Math.PI * this.radius };

1 1276

Can you write a random integers function to print integers with in a range?

1 1399

What is the output of below code var car = new Vehicle("Honda", "white", "2010", "UK"); console.log(car); function Vehicle(model, color, year, country) { this.model = model; this.color = color; this.year = year; this.country = country; }

1 1826

Event handler Example

1 1169

What will be the output of the code below? var Y = 1; if (function F(){}) { y += Typeof F; } console.log(y);

1 1498

What will be the output of the following code? //nfe (named function expression) var Foo = Function Bar() { return 7; }; typeof Bar();

1 1419

What is a “closure” in JavaScript? Provide an example

1 1266

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

1 1146

Explain the difference between == and === in JavaScript.

1 1232

What is the difference between synchronous and asynchronous JavaScrip

1 1307

What is the event loop in JavaScript?

1 1267

What is a Promise in JavaScript?

1 1237

What is this in JavaScript?

1 1227

What is call(), apply(), and bind()?

1 1199

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Un-Answered Questions { JavaScript }

What is use strict in javascript?

878

What value does prompt() return if the user clicked the cancel button?

819

What are the new ways to define a variable in Javascript?

977

Is webassembly faster than javascript?

894

Some XYZ company is arranging for online aptitude tests. Draw detailed E-R diagram for the same..

2054

What is the disadvantage of using innerhtml in javascript?

1123

What is the difference between write and writeln in javascript?

842

Where do you write javascript?

866

Where do I write javascript code?

968

How to use one javascript function for multiple input fields?

1967

Why is object naming important to use in javascript?

904

What are exports & imports?

887

What is spread syntax?

883

Why is var better than let?

1017

What does the attribute defer/async do when added to the script tag?

910

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