79 interview questions on Javascript for developers (2024)

Hard

8 votes1996 runs1 comment

Which of the following equality(s) are true? 0 == '', 'f' + 1 == 'f1'

Front-end developer

javascript

equality

Jean-marie Cléryat Jan 4, 2022

Hard

7 votes1969 runs2 comments

Write a Javascript code that prints the indexes of an array.

Front-end developer

array

for loop

Jean-marie Cléryat Nov 8, 2023

Easy

6 votes2005 runs0 comment

Which of the following is the most optimized method for creating a literal object?

Front-end developer

javascript

objects

Jean-marie Cléryat Jan 4, 2022

Hard

6 votes1995 runs0 comment

Invert a string in Javascript

Front-end developer

arrays

strings

Jean-marie Cléryat Jan 4, 2022

Hard

5 votes2060 runs0 comment

What will this code display?

Front-end developer

javascript

function

identity

Jean-marie Cléryat Jan 4, 2022

Hard

5 votes2025 runs1 comment

What is the value of `obj.hello` after executing these few lines of code?

Front-end developer

objects

arrays

strings

Jean-marie Cléryat Oct 20, 2023

Hard

5 votes221 runs1 comment

How to overwrite a property in an object in Javascript

Front-end developer

objects

duplicates

Vincent Cotroat Sep 19, 2022

Hard

4 votes2032 runs0 comment

Explain the difference between `proto` and `prototype` in Javascript

Front-end developer

prototype

constructor

Jean-marie Cléryat Jan 4, 2022

Medium

4 votes2026 runs0 comment

How to make an AJAX call to an external domain that makes public data available.

Front-end developer

ajax

authentication

Jean-marie Cléryat Jan 4, 2022

Hard

4 votes2008 runs1 comment

How to call a function inside a function in Javascript

Front-end developer

functions

objects

Jean-marie Cléryat Jan 4, 2022

Easy

3 votes2045 runs

2 comments

Write a Javascript code that displays the contents of the table : Peter, Paul, Jacques, and the length of the table.

Front-end developer

arrays

console.log

push

Jean-marie Cléryat Jan 4, 2022

Hard

3 votes2033 runs0 comment

Identify the reasons why this code will not work correctly:

Front-end developer

javascript

html

form

Jean-marie Cléryat Jan 4, 2022

Hard

3 votes1987 runs0 comment

Explain the 2 phases of event propagation in the DOM.

Front-end developer

event

event propagation

Jean-marie Cléryat Jan 4, 2022

Hard

3 votes1985 runs0 comment

What will be the first thing that the following code displays?

Front-end developer

inheritance

prototype

constructor

Jean-marie Cléryat Jan 4, 2022

Medium

3 votes1984 runs0 comment

Write a Javascript code that will display the letters A, B, C, D in the console.

Front-end developer

array

function

Jean-marie Cléryat Jan 4, 2022

Medium

3 votes263 runs1 comment

Print the value of the variable name and age in the function sayHi()

Front-end developer

functions

variables

Vincent Cotroat Sep 19, 2022

Medium

3 votes219 runs0 comment

Compare two numbers in Javascript

Front-end developer

equality

comparison

type

Vincent Cotroat Sep 19, 2022

Hard

2 votes2053 runs0 comment

Which of the following features are part of version ES2015(formerly ES6)?

Front-end developer

es6

promises

arrow functions

Jean-marie Cléryat Jan 4, 2022

Hard

2 votes2019 runs1 comment

Which statements are true about JavaScript Strict Mode?

Front-end developer

javascript

strict mode

Jean-marie Cléryat Jan 4, 2022

Hard

2 votes2008 runs0 comment

Which of the following equality(s) returns`true`?

Front-end developer

javascript

NaN

Jean-marie Cléryat Jan 4, 2022

79 interview questions on Javascriptfor developers (2024)

Test your technical skills before an interview of Javascript with 79 corrected questions. Beginner, Intermediate or Expert level.

Which of the following equality(s) are true? 0 == '', 'f' + 1 == 'f1'

Write a Javascript code that prints the indexes of an array.

Which of the following is the most optimized method for creating a literal object?

Invert a string in Javascript

What will this code display?

What is the value of `obj.hello` after executing these few lines of code?

How to overwrite a property in an object in Javascript

Explain the difference between `proto` and `prototype` in Javascript

How to make an AJAX call to an external domain that makes public data available.

How to call a function inside a function in Javascript

Write a Javascript code that displays the contents of the table : Peter, Paul, Jacques, and the length of the table.

Identify the reasons why this code will not work correctly:

Explain the 2 phases of event propagation in the DOM.

What will be the first thing that the following code displays?

Write a Javascript code that will display the letters A, B, C, D in the console.

Print the value of the variable name and age in the function sayHi()

Compare two numbers in Javascript

Which of the following features are part of version ES2015(formerly ES6)?

Which statements are true about JavaScript Strict Mode?

Which of the following equality(s) returns`true`?

79 interview questions on Javascriptfor developers (2024)

Test your technical skills before an interview of Javascript with 79 corrected questions. Beginner, Intermediate or Expert level.

Which of the following equality(s) are true? 0 == '', 'f' + 1 == 'f1'

Write a Javascript code that prints the indexes of an array.

Which of the following is the **most optimized** method for creating a literal object?

Invert a string in Javascript

What will this code display?

What is the value of `obj.hello` after executing these few lines of code?

How to overwrite a property in an object in Javascript

Explain the difference between `__proto__` and `prototype` in Javascript

How to make an AJAX call to an external domain that makes public data available.

How to call a function inside a function in Javascript

Write a Javascript code that displays the contents of the table : Peter, Paul, Jacques, and the length of the table.

Identify the reasons why this code will not work correctly:

Explain the 2 phases of event propagation in the DOM.

What will be the first thing that the following code displays?

Write a Javascript code that will display the letters A, B, C, D in the console.

Print the value of the variable name and age in the function sayHi()

Compare two numbers in Javascript

Which of the following features are part of version ES2015(formerly ES6)?

Which statements are true about JavaScript Strict Mode?

Which of the following equality(s) returns`true`?

Which of the following is the most optimized method for creating a literal object?

Explain the difference between `proto` and `prototype` in Javascript