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Frontend Developer Practice Test

20 multiple choice questions for frontend developers: JavaScript, React, HTML and CSS, accessibility, Next.js and web performance.

Questions
20
Time
20 min
Pass mark
60%

No account or email needed.

About this test

This test is built around the Frontend Developer (React and Next.js) role. It mixes core JavaScript and React with the things frontend work depends on every day: HTML and CSS, accessibility, how Next.js renders pages, and what makes a page feel fast.

It is practice only and is not part of any job application.

What it covers

The question set has 26 questions: 15 easy, 11 medium and 0 hard. Each attempt draws 20 of them at random, so a second try is not the same test.

  • Accessibility (3)
  • HTML and CSS (5)
  • JavaScript (6)
  • Next.js (4)
  • React (6)
  • Web performance (2)

Try a few sample questions

These are real questions from the set, with the answers and a short explanation. Read the question, decide, then open it to check.

Sample 1 · JavaScript · easyWhat does typeof null return in JavaScript?Show the answer
  • "null"
  • "object"Correct
  • "undefined"
  • "number"

This is a long-standing quirk of the language. typeof null is "object", so check for null with value === null instead.

Sample 2 · React · easyWhat does JSX turn into when your code is built?Show the answer
  • HTML strings
  • Function calls that create React elementsCorrect
  • CSS rules
  • Web components

JSX is syntax for creating elements. A compiler turns it into function calls such as React.createElement or the jsx runtime.

Sample 3 · HTML and CSS · easyWhich CSS declaration turns an element into a flex container?Show the answer
  • position: flex
  • display: flexCorrect
  • flex: container
  • layout: flex

display: flex makes the element a flex container, so its direct children become flex items.

How it works

  • 20 multiple choice questions, drawn at random from a larger set.
  • 20 minutes on the clock. The test submits itself when time runs out.
  • Pass mark: 60%.
  • No marks are taken off for wrong answers, so answer every question.
  • Some questions have more than one correct answer. You must pick all of them to score.
  • When you finish you see your score, the correct answers and a short explanation for each.
  • Your answers save as you go, so a dropped connection will not lose your work.
  • Please stay on the test page. Switching to another tab or window is recorded and you will see a warning.
  • Copying text, printing and screenshots are not allowed during the test.

This role is open

This test is built around the Frontend Developer (React and Next.js) role on our jobs board. Taking it is not part of the application.

See the role

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