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
3812
To review
3
80 questions
Hard
10 votes2285 runs3 comments
Hard
8 votes2321 runs
2 comments
Hard
7 votes2397 runs0 comment

What will this code display?

Front-end developer
javascript
function
identity
Jean-marie Cléryat Jan 4, 2022
Hard
7 votes2342 runs
1 comment

Invert a string in Javascript

Front-end developer
arrays
strings
Jean-marie Cléryat Jan 4, 2022
Easy
7 votes2316 runs0 comment
Hard
5 votes2366 runs0 comment
Medium
5 votes2302 runs0 comment
Hard
5 votes2290 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 votes249 runs1 comment
Hard
4 votes2443 runs1 comment
Hard
4 votes2352 runs1 comment
Hard
4 votes2339 runs
2 comments
Hard
4 votes2328 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 votes2404 runs
1 comment
Hard
3 votes2382 runs1 comment
Hard
3 votes2367 runs
1 comment
Hard
3 votes2367 runs3 comments

Write a function that returns a string 'Haha!'

Front-end developer
functions
return
Jean-marie Cléryat Jan 4, 2022
Hard
3 votes2349 runs
1 comment
Hard
3 votes2308 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