HTML/CSS, JavaScript, and React Online Test
TestDome skill assessments are used by more than 6,000 companies and 450,000 individual test takers.
For Jobseekers
Practice your skills and earn a certificate of achievement when you score in the top 25%.
Take a Practice TestFor Companies
Test how candidates think, strategize, and problem solve so you can interview the best.
Sign Up to Offer This TestTestDome Skill Assessments
Used by over 450,000 jobseekers
Trusted by over 6,000 companies
Premium questions with real-world problems
The HTML/CSS, JavaScript, and React online test assesses candidates' knowledge of HTML, CSS , JavaScript, and React as well as their ability to combine those technologies and take advantage of commonly used parts of Bootstrap.
It's an ideal test for pre-employment screening. A good front-end developer should be able to combine HTML, CSS, JavaScript, and React to create a dynamic and interactive user interface.
This online test requires candidates to solve common HTML/CSS, JavaScript, and React coding problems.
TestDome is trusted by businesses large and small
We’re top rated for our tests’ quality and reasonable completion time
"TestDome doesn't take the candidate an inordinate amount of time. It simulates working pressure with the time limits."
- Jan O., G2 reviewer
Free Sample Questions for HTML/CSS, JavaScript, and React Test
Our sample questions are free for companies to use on a trial plan. See more about our premium questions for paid plans below.
Ensure
3min
-
Easy
Easy
-
CODE
JavaScript
Error handling
Language
Public
JavaScript
JavaScript is the programming language of HTML and the web. It's an essential skill for any programmer working with websites and web technologies.
Error handling
Error handling is essential for properly implementing recovery procedures from errors present in a software application.
Language
A programmer should use a language as a tool, always taking advantage of language-specific data types and built-in functions.
Public
Public questions (free account) are common interview questions. They are great for practicing, or if you want to filter candidates using the classic problems.
Implement the ensure function so that it throws an error if called without arguments or the argument is undefined. Otherwise it should return the given value.
Avatar
7min
-
Easy
Easy
-
CODE
HTML/CSS
Borders
Element size
Styling
Public
HTML/CSS
HTML is the standard markup language for creating web pages. It's an essential skill for anyone creating web pages of any complexity.
Borders
Borders can be applied to most HTML elements within the body. This is one of the most used element decorations.
Element size
Setting the size of the elements on a web page is one of the basic things that any web developer or designer should know.
Styling
Styling user interfaces according to the specification is a daily routine for a front-end developer.
Public
Public questions (free account) are common interview questions. They are great for practicing, or if you want to filter candidates using the classic problems.
Every user on your website has an image avatar that is displayed when they post a comment. You want to style these images differently from other images on your site. Add a CSS class named avatar that fulfils the following requirements:
- The avatar's border is rounded, so that it appears as a circle.
- The avatar's width and height are both 150px.
- The avatar has a solid border, has a width of 2px, and be colored gray.
For example, the avatar in the template should look like:
Focus
15min
-
Easy
Easy
-
CODE
React
Components
Public
React
React is a JavaScript library for building user interfaces. As one of the most widely used frameworks it's important for most JavaScript developers to have a working knowledge of.
Components
Components are used in many frameworks and languages as the building blocks of an application.
Public
Public questions (free account) are common interview questions. They are great for practicing, or if you want to filter candidates using the classic problems.
The TextInput component renders an input element in the DOM and accepts a ref that is forwarded to that input element. Finish the FocusableInput component:
- The component should accept a focused prop.
- When the focused prop is changed from false to true, and the input is not focused, it should receive the focus.
- If on mounting the focused prop is true, the input should receive the focus.
Take The Test
Practice your skills.
Practice your skills.
Offer This Test
Sign up for a trial plan.
Sign up for a trial plan.
Premium Questions for HTML/CSS, JavaScript, and React Test
TestDome offers a premium questions library with 1000+ unique, hand-crafted questions whose answers can’t be found online. If you spot an answer somewhere online, we’ll give you a refund.
Question Names
These premium questions are included in this pre-built test and can be added to any multi-skill test. Please sign up for a paid plan to view the questions in detail.
Filter, Positive Numbers, Links, Function Wrapper, Double, Truthy Expressions, Word Count, New Folder, Log Patch, Loading Bar, Tab Strip, Contact Form, Email Form, Background Wrapper, Segment, Hobbies, A Tag, Ad, Addition, Article Style, Baby Names, Bookmark, Christmas Tree, Cities, Confirm, Date Transform, Editor, Format Table, Height, Hide Button, Keywords, Label Color, Link, Loading, Log Parser, Logo, Paragraph, Product Rating, Products, Row Appender, Scale Font Size, Share Button, Shirts, Snapshot, Timesheet, Upload, Username, Vectors, Warehouse, Widgets, Timer, Screen, Email Tables, Tooltip Component, Ice Cream Flavors, List Wrapper, Breakfast Menu, Array Search, iframe, TestDome Logo, Post Comment, Shopping List, Cards, Reorder, Validation, Table of Names, Blog, Screen Reader, Post Comment, Theme Context Switcher, Player Status, Simple Calculator, Data Entry, Reorder, Toggle Options Visibility, Cards Widget, Product Rating, Error Catcher, DetailsCovered Skills
Testing of these skills is covered in this pre-built test because they’re closely related. On our paid plan, you can easily create your own custom multi-skill tests.
JavaScriptJavaScript
JavaScript is the programming language of HTML and the web. It's an essential skill for any programmer working with websites and web technologies.
Arrays
An array is a container of a fixed number of objects of a similar type. It is a fundamental component of most programming languages.
Closures
Closures are an important concept in any programming language in which functions are first-class citizens.
HTML/CSS
HTML is the standard markup language for creating web pages. It's an essential skill for anyone creating web pages of any complexity.
CSS selectors
Selectors are a programming pattern that can be used to select an element from a container. They are primarily used in technologies such as CSS and jQuery to apply styles to groups of elements.
Styling
Styling user interfaces according to the specification is a daily routine for a front-end developer.
Exceptions
Exceptions exist in most modern programming languages, making it important for a programmer to understand them and know how to handle them.
DOM manipulation
Dynamically accessing and updating user interface elements is an important part of most modern web applications.
Event handling
Event-based design patterns are very common in modern applications, especially in the development of user interfaces.
Language
A programmer should use a language as a tool, always taking advantage of language-specific data types and built-in functions.
Strings
The string data structure is used to represent text. It is one of the most commonly used data structures. Therefore, every programmer should be skilled at string manipulation.
Monkey patching
Monkey Patching is a method of either adding new or overriding existing functionality without the creation of a new type. As such it's an important tool for developers to be familiar with.
HTML5
HTML5 is now supported in all modern browsers, making it important for front-end developers to know how to use its features.
React
React is a JavaScript library for building user interfaces. As one of the most widely used frameworks it's important for most JavaScript developers to have a working knowledge of.
Components
Components are used in many frameworks and languages as the building blocks of an application.
Conditional rendering
Conditional rendering in React is rendering different components depending on the application state. It is commonly used and, as such, is important for all developers.
VDOM
Many modern web frameworks provide a virtual DOM that can be used to improve performance and maintainability of large web applications - as such, it's important for web developers to have a solid understanding of how to interact with both the VDOM and DOM.
Arithmetic
Arithmetic is a fundamental branch of mathematics. An understanding of arithmetic concepts, and their application, is important for every candidate.
Iteration
Iteration is the act of repeating a process, or cycling through a collection. Iteration is one of the fundamental flow control tools available to developers.
Attribute manipulation
Getting and setting HTML attributes is one of the most common coding tasks of that changes something on a web page.
Element spacing
Setting the margins and padding of the elements on a web page is one of the basic things that any web developer or designer should know.
CSS advanced
Cascading Style Sheets are the styling language of the web. Knowledge about advanced CSS features is required for seasoned front-end developers.
Element size
Setting the size of the elements on a web page is one of the basic things that any web developer or designer should know.
Flexbox
The Flexible Box Layout Module makes it easier to design a flexible responsive layout structure.
Positioning
Dynamic positioning of user interface elements depending on resolution is more important than ever in modern applications, making this important for a front-end developer.
Bookmarks
A bookmark is a hyperlink that points to a location within a document, which is defined by a name that is assigned to an element. Bookmarks are used when we need to jump to a specific location within a document.
Elements and attributes
Defining elements and their attributes is the first process in creating an HTML page.
Fonts
Setting the font name or size is part of creating any web page.
Dialog box
Dialog box, a small window that pops-up, is a common way for communicating information to the user and prompting them for a response.
Regex
A regular expression (regex) is a special text string for describing a search pattern. It is a common way for extracting data from text.
Objects
An object is a self-contained component which consists of methods and properties to make a particular type of data useful. Knowing how to create objects, and work with them, is an essential part of OOP.
Asynchronous calls
Calling methods asynchronously is a common task for programmers.
Hyperlink
Hyperlink, or simply a link, is a reference to data that the reader can follow by clicking or tapping. There's no web page without a hyperlink.
Animation
Animation is the process in which images or objects are manipulated to appear as if they are moving. It's a powerful effect that is important for UI designers to understand and be able to use.
Serialization
Familiarity with data serialization to and from formats such as XML and JSON is important as it is commonly used for interprocess communication
XML
Extensible Markup Language (XML) is a markup language that defines a set of rules for encoding documents in a format that is both human-readable and machine-readable. The design goals of XML emphasize simplicity, generality, and usability across the Internet. This is one of the most used formats for exchanging data over the web.
JSON
JSON is an open-standard format that uses human-readable text to transmit data objects consisting of attribute-value pairs. It's the most common data format used for asynchronous browser/server communication.
Sorting
Every programmer should be familiar with data-sorting methods, as sorting is very common in data-analysis processes.
Content manipulation
Adding or modifying content is the most common task when developing dynamic web pages.
Forms
Forms provide a method of grouping inputs and collecting user data. As such, they are important for all front end developers.
Tables
A table stores data as rows and columns. From databases to HTML layouts, as a data structure they are ubiquitous. They are an important structure for developers to understand and know how to use.
Callback
A callback is a piece of code that can be passed as an argument to another bit of code. It's a very common pattern that has a wide variety of uses, and as such it's important to understand.
Bug fixing
Everyone makes mistakes. A good programmer should be able to find and fix a bug in their or someone else's code.
Classes
A class is one of the most widely used and primary structures used in object-oriented programming. As such it's important for any developer to have a working knowledge of how to use it.
ECMAScript 2015
ECMAScript 2015 adds a significant number of features to JavaScript, including classes, modules and range based loops. As such it's important for any JavaScript developer to understand.
Borders
Borders can be applied to most HTML elements within the body. This is one of the most used element decorations.
Inline styles
Inline styles are styles that are applied directly on elements. This is one of the ways for applying styles and for some scenarios, such as for email, is the only supported way.
Portals
Portals are a first-class way to render children into a DOM node that exists outside the DOM hierarchy of the parent component. As such, they are a very convenient tool for all developers who need to interact with a virtual DOM.
Responsive design
Anyone who works with web should know how to properly implement responsive web design that makes web pages render well on a variety of devices and screen sizes.
Higher order components
A higher-order component (HOC) is an advanced technique in React for reusing component logic. HOCs are not part of the React API, they are a pattern that emerges from React’s compositional nature.
Selectors
Selectors are a programming pattern that can be used to select an element from a container. They are primarily used in technologies such as CSS and jQuery to apply styles to groups of elements.
Recursion
A good programmer should be familiar with when to use recursive functions, since they can provide elegant solutions for complex problems.
IFrame
The HTML Inline Frame element (iframe) represents a nested browsing context, embedding another HTML page into the current one. Web developers often use it to display content within other content.
CSS layout
Cascading Style Sheets are the styling language of the web. For a front-end developer, a knowledge of CSS layouts is required.
Managing state
Knowing how to overcome statelessness, the intrinsic limitation of web programming, is a very important skill for a web developer.
Semantic tags
HTML5 introduced semantic tags, which can greatly improve the level of automated analysis that can be done on documents, as well as improve the readability of HTML.
Accessibility
Accessibility refers to the design of products, devices, services, or environments for people who experience disabilities. It's important for all designers and developers to know how to optimize for people who experience disabilities.
React Hooks
React Hooks allow developers to use state and other React features without writing a class. Hooks allow developers to reuse stateful logic without changing the component hierarchy.
Context
React Context provides a way to pass data without using props through every level of the tree.
Effect Hook
Using a React Effect Hook allows you to set up a subscription to DOM changes and perform side effects.
State Hook
Using a React State Hook allows you to preserve state between re-renders in a manner that doesn't require render props and higher-order components patterns, which simplifies code.
Reducer Hook
Using a React Reducer Hook allows you to pass callbacks with values between components, which simplifies code by removing the need to pass callbacks through every level of a component tree.
Data binding
Data binding is a technique for synchronizing data between a component and DOM. For this reason, it’s important for all web developers.
Error boundaries
Error boundaries are React components that catch JavaScript errors anywhere in their child component tree and display a fallback UI instead of the component tree that crashed. Since they are one of the basic building blocks of error handling, they are important for all React developers.
Recommended Job Roles
These are the job roles that we recommend for the HTML/CSS, JavaScript, and React online test.
JavaScript Developer
React Developer
UI/UX Developer
Web Front-End Developer
Take The Test
Practice your skills.
Practice your skills.
View Test Pricing
Pick the number of tests you need.
Pick the number of tests you need.
Pass/fail grouping
Our tests are designed to put candidates into either the pass group or the fail group so you can find the best candidates faster.
Full customization
We have pre-built tests and questions, but you can customize them however you like. Change the pass/fail scores, time requirements, and more.
Cheating protection
Use tests that solve real-world problems, with no answers that can be easily found online. Because we test performance and skills (not information), we allow the use of online resources, just like in real life. Copy/paste prevention and online proctoring via webcam prevent cheating.
Candidate reporting
Get an overview into the percentage of passes and fails. Then dive deeper into the results of your top candidates to select who goes onto the next phase of hiring.
Learn more
How TestDome works
1. Choose or create a test
2. Share your test via URL or email
3. Review overall results and pass/fail grouping
4. Dive deeper into individual results
Excellent support & free concierge service
We offer fast, hands-on support for any question or concern you might have. If you want help with building a custom test or inviting candidates, we’ll handle everything for you.
Contact Support for any questions or to request our free concierge service.
