Frontend developer interview questions are integral to helping you clear your interview. However, what questions you will be asked in your interview remains a critical part to deal with.
To help you prepare for your front-end developer interview, we will discuss the top front end developer interview questions and answers. These front end developer interview questions and answers are categorized from beginner to advanced so you can prepare step by step.
Ideally, you should prepare for every question, but if you feel stuck at any point, then join our free full-stack web development course to get complete guidance.
Before discussing the interview questions on front-end development, let’s quickly get an idea of what front-end development is.
What is Front-End Development?
Front-end development is the practice of creating the parts of websites or web applications that users interact with. CSS, HTML, and JavaScript are some of the languages used to build interactive and responsive interfaces that can work across different browsers and platforms. Front end developers basically create fast and accessible websites by focusing on the user experience and visual design elements. Becoming Front end developers is a good career option for taking high-paying jobs.
Now that we have a glimpse of the front-end development concept, let’s head to the main event. These are some of the most commonly asked interview questions on front end developer roles that recruiters use to test both theory and practical skills.
Whether you’re preparing for frontend developer interview questions for freshers or advanced-level coding rounds, it’s important to cover everything from HTML basics to front end JavaScript interview questions
Frontend Developer Interview Questions for Freshers
If you’re a beginner, these frontend developer interview questions for freshers will help you build a solid foundation. These front end developer basic interview questions cover HTML, CSS, and beginner-level concepts essential for entry-level jobs:
Q1. What are the differences between an id and a class in HTML/CSS?
Ans. An id is a unique identifier used only once in every HTML page. In CSS, it is selected as a hash symbol (#). On the other hand, a class, represented as a dot (.), can be applied to multiple elements. Because IDs have higher CSS specificity than classes, they will override class styles if both target the same element. IDs should be used for unique elements like headers or main sections, and classes for styling multiple elements with common properties.
Q2. Explain the box model in CSS.
Ans. The CSS box model is a concept that describes how each HTML element is structured in a rectangular box with four distinct areas. They are:
Content– The innermost section where text and images appear.
Padding- It is the space between the content and the border.
Border- This refers to the outermost part of the padding surrounding the element.
Controlling each layer separately allows you to customize the appearance of each element in the user interface.
Q3. What distinguishes inline, inline-block, and block elements?
Ans.
Inline: These elements lack a specified width or height. Instead, they do not start on a new line and only occupy the width necessary based on their content. Additionally, their layout can be affected by vertical-align properties, which determine how they align with surrounding inline or inline-block elements.
Inline-block: Inline-block is a hybrid technique that merges the advantages of both inline and block elements: it allows elements to flow horizontally like inline elements while respecting width, height, and margin/padding properties like block elements. This approach is particularly useful for creating horizontal layouts or designing components such as buttons that need specific dimensions but sit side-by-side.
Block: Block elements extend across the entire available width and begin on a new line—examples include divs, paragraphs, and headings. They stack vertically, and you can specify width, height, margin, and padding on all sides.
Q4. What are some effective SEO best practices for structuring an HTML document?
Ans. From an HTML perspective:
Use Semantic HTML- To provide meaningful structure, consider these tags:
| <header>, <nav>, <main>, <article>, <section>, and <footer>. |
Proper Heading Hierarchy- Use headings from <h1> to <h6> and ensure that <h1> is placed at least once per page for the main title. <h1> can be later followed by <h2>, <h3>, etc.
Meta Tags- Include relevant <meta> tags, including description, keywords, and viewport, to present the website’s metadata.
Alt Attributes on images- Add alt attributes to images to describe their content, improving accessibility and SEO.
More importantly, one should consider the following aspects as well:
Internal Linking: Ensure interlinking to connect content throughout your website. It makes it easier for search engines to explore and understand how your website is organized.
Mobile-Friendly Design: Keep a mobile-first mindset while coding your site and CSS. This will ensure a better user experience leading to better rankings on search engines as majority of users will interact with your website through mobile.
Fast Loading Times: Optimize images, implement efficient code, and leverage caching to enhance page load times. Faster load speeds increase your page’s competitive edge in SERP rankings.
Q5. Can you explain what the Document Object Model (DOM) is?
Ans. The Document Object Model, or DOM, is an API for web documents. It represents HTML documents as a tree-like structure in which each HTML element eventually becomes a node JavaScript can access and manipulate.
This allows developers to dynamically change the content, structure, and style of web pages in real-time. The DOM is essential for creating interactive and responsive websites, as it provides a bridge between the static HTML and the dynamic behavior of modern web applications.
Frontend Developer Interview Questions – Intermediate
Q6. What is the difference between the em and rem units?
Ans. em and rem units are relative units of measurement, but relative to different things. For example, em units are relative to the parent element’s font size. So, if a parent has a 16px font size, 1em equals 16px. On the other hand, rem is related to the web page’s root element’s font size, typically 16px by default, making 1rem = 16px regardless of parent elements.
Q7. How do you create a flexbox layout?
Ans. Consider these two steps to create a flexbox layout:
First, set the parent container to display: flex to create a flex container.
Second, apply flexbox properties such as justify-content (for horizontal alignment), align-items (for vertical alignment), and flex-direction (for layout direction) to manage how child elements are arranged and spaced within the container.
Q8. Could you explain CSS specificity and its functioning?
Ans. CSS specificity is a scoring system that determines the styles applied when multiple CSS rules target the same element. The browser determines specificity through a point system: inline styles are worth 1000 points, IDs are worth 100 points, classes, attributes, and pseudo-classes each earn 10 points, while elements and pseudo-elements score 1 point.
- First, any inline style will override all other styles.
- Second, any ID-based style will override all styles except inline styles.
- Third, styles applied through class-based selectors will override all styles except inline styles and those based on IDs.
- Finally, type selectors can be overridden by other types of selectors.
Q9. What is the difference between == and === in JavaScript?
Ans. == operator (double-equal operator) checks the values of the operands and returns true if the values are the same. Whereas the === operator (triple-equal operator) is not limited to the tasks of the == operator, it also checks the values of the different types of the operands.
It returns true only if the values and the type of the operands are the same. This is one of the most popular front end JavaScript interview questions, as recruiters want to check your understanding of strict equality.
Q10. What’s the difference between null and undefined in JS?
Ans. Undefined indicates that a variable has been declared but not given a specific value, or a function does not explicitly return anything. It shows that something exists but doesn’t have a value yet. On the other hand, null is a deliberate assignment by the developer to represent ‘no value’ or ’empty,’ typically indicating the absence of an object or data.
Read to know more – Top 5 Full-Stack Web Development Courses in Hyderabad
Q11. What is Angular?
Ans. Angular is an open-source front-end framework developed and maintained by Google. It is mainly used for creating dynamic, single-page web applications (SPAs) and is built with TypeScript, which is a superset of JavaScript.
Some of the key aspects of Angular include:
Component-Based Architecture- Angular is based on a component-based structure, where everything is organized into reusable components. This helps it maintain large applications.
Modularization- This approach breaks down the application into smaller, reusable modules. It simplifies development and maintenance and allows teams to work on different parts simultaneously, improving efficiency and flexibility.
Two-Way Data Binding- This allows data to sync automatically between the model and the view. When the model’s data changes, the view updates automatically, and the other way around, without needing manual DOM updates.
Templating- Uses templates to define the view, allowing for dynamic and efficient UI updates that keep the interface responsive and up-to-date. This approach helps developers create flexible and scalable user interfaces that can adapt to changing data and user interactions.
Apart from CSS and HTML, you should also be ready for front end JavaScript interview questions, as they test logical problem-solving and DOM manipulation skills. You can learn this skills from many institutions, read this blog to know the best guide for Website development Course to choose the best one.
Advanced Frontend Developer Interview Questions
Q12. What is server-side rendering, and when should you use it?
Ans. SSR, or server-side rendering, is when the HTML is generated on the server before it is sent to the browser. With SSR, the server handles the application logic, retrieves data, and renders the full HTML markup, so users see a complete page immediately upon loading.
I would use SSR when the SEO is critical, since search engines can easily crawl the pre-rendered HTML. Especially when initial page load performance is vital for user experience, or when targeting users with slower devices or poor internet connections. SSR can be considered valuable for content-heavy sites, e-commerce platforms, or marketing pages.
Q13. What is Vue-loader?
Ans. Vue Loader is a Webpack loader for VueJS, allowing developers to write Vue components in the ‘.vue’ file format. It allows VueJS applications to use Single File Components (SFCs), integrating HTML, CSS, and JavaScript into a single file. These components are bundled into JavaScript modules that browsers can interpret, streamlining component-based development in VueJS projects.
Q14. Explain vue plugin.
Ans. Vue plugin helps developers add global-level features to Vue. These plugins can manage functionalities like routing, state management, and UI component libraries, making development more modular and efficient. By integrating plugins, developers can easily extend Vue’s core capabilities without altering its source code.
Q15. How do you merge the rows and columns of an HTML table?
Ans. To merge the rows and columns, use the ‘colspan’ and ‘rowspan’ attributes with the <td> element, specifying the number of columns or rows to merge by passing a numeric value to each attribute. The columns can be combined using the colspan attribute, and the rows can be merged with the rowspan attribute.
Read more – Learn Full-Stack-Web Development: No Experience Needed
Q16. What is a Content Security Policy (CSP), and in what ways does it enhance the security of web applications?
Ans. CSP is a security header that tells the browser which sources are allowed to load resources, like scripts, stylesheets, images, and fonts on your webpage. Content Security Policy also improves security by preventing Cross-Site Scripting (XSS) attacks, even when the attacker injects malicious code into your page.
Note that if you’re preparing for WordPress-related roles, you may also face WordPress front-end developer interview questions that focus on theme customization, responsive design, and plugin integration.
Wrap Up
These were some of the most commonly asked frontend developer interview questions. Whether you are a complete fresher or an experienced professional, these basic to advanced interview questions will help you clear your interview with flying colors and make you a worthy candidate for top companies. Also note that different companies may ask anything from front end developer basic interview questions to more advanced ones like WordPress front end developer interview questions, depending on the role you apply for. By practicing every frontend developer interview question, you’ll develop the clarity and confidence needed to excel in any interview round.
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