fr
fr

80 interview questions on Javascriptfor developers (2025)

Test your technical skills before an interview of Javascript with 80 corrected questions. Beginner, Intermediate or Expert level.

Technology
Profession
Test
Sort by
Newest
Most popular
Last review
Filter by
Published
3806
To review
8
80 questions
Hard
10 votes2271 runs3 comments
Hard
8 votes2307 runs
2 comments
Hard
7 votes2379 runs0 comment

What will this code display?

Front-end developer
javascript
function
identity
Jean-marie Cléryat Jan 4, 2022
Hard
7 votes2328 runs
1 comment

Invert a string in Javascript

Front-end developer
arrays
strings
Jean-marie Cléryat Jan 4, 2022
Easy
7 votes2300 runs0 comment
Hard
5 votes2350 runs0 comment
Medium
5 votes2284 runs0 comment
Hard
5 votes2277 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
Hard
5 votes248 runs1 comment
Hard
4 votes2429 runs1 comment
Hard
4 votes2333 runs1 comment
Hard
4 votes2320 runs
2 comments
Hard
4 votes2306 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 votes2385 runs
1 comment
Hard
3 votes2364 runs1 comment
Hard
3 votes2352 runs
1 comment
Hard
3 votes2348 runs3 comments

Write a function that returns a string 'Haha!'

Front-end developer
functions
return
Jean-marie Cléryat Jan 4, 2022
Hard
3 votes2330 runs
1 comment
Hard
3 votes2288 runs
2 comments

Which of the following code will log the message 'baz'?

Front-end developer
javascript
function
prototype
Jean-marie Cléryat Jan 4, 2022