Most Asked Front End Developer Interview Questions

Front end developers are professionals who develop the part of the website with which the users interact. They are responsible for the development of a website’s graphical user interface using CSS, HTML and Javascript.

Front end developers are professionals who develop the part of the website with which the users interact. They are responsible for the development of a website’s graphical user interface using CSS, HTML and Javascript. The profile of a front end developer is technical in nature due to which they must be technically sound in their domain. In this article, we will be discussing the most asked front end developer interview questions.

Top Front End Developer Interview Questions

Let us now discuss the probable interview questions for the position of front end developer.

Q1. How do you optimize the asset resources of a website?

Ans. Assets resources of a website including images, scripts, styles and external media can be optimized through three different methods:

1. Making all the assets lightweight so that they are easy to download
2. Using Content Delivery Network for optimizing assets
3. Reducing DNS lookups while hosting assets on different domains
4. Using CSS Sprites
5. Disabling etags

Q2. How do you improve website performance?

Ans. The following methods can help in improving website performance:

• Minimize External HTTP Requests
• Optimize JS and CSS Performance
• Minify JS, CSS and HTML
• Compress Images and Files
• Prefetch should be Enable
• Use CDN and Caching to increase speed

Q3. What is the use of CORS?

Ans. Through Cross-Origin Resource Sharing (CORS), you can make requests from one website to another. For security purposes, browsers are not allowed for loading requests to other domains when those requests are generated by scripts. CORS addresses the issue by supplying a header that defines which domains can make the XMLHttpRequests.

Q4. Explain the CSS “box model” and its layout components?

Ans. The CSS box model is a rectangular layout paradigm for HTML elements that consists of the following:

• Content: The content of the box, where images and text appear
• Padding – A transparent area that surrounds the content
• Border – A border that surrounds the padding and content
• Margin – A transparent area that surrounds the border

Q5. Explain the fundamental principles of design.

Ans. One of the front end developer interview questions is based on the fundamental principles of design. These include:

• BALANCE offers stability and structure to the design. It can be defined as the weight distributed across the design by the placement of elements.
• PROXIMITY means the relationship between different elements i.e.elements should be visually connected in some way.
• ALIGNMENT  allows the creation of order and organization. By aligning elements, a visual connection with each other can be created.
• REPETITION  means tying together individual elements and leading to a stronger design. It helps in association and consistency. It can create rhythm.
• CONTRAST is the juxtaposition of opposing elements and it allows us to highlight the key elements within the design.
• SPACE  refers to the distance between or within elements. Both positive and negative space are crucial factors that must be considered in every design.

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Q6. What is the importance of tableless web design?

Ans. Tableless web design is a web design method that uses CSS to arrange elements and tags on the web page instead of using HTML tables for page layout control. Tableless web designs have the following:

1. The webpage content becomes sleeker and manageable.
2. They are more accessible, faster and easier, especially when you need to maintain pages.
3. These have faster page load time and the ability to allow search engines to allow accessing important content first. This is why tableless web designs are more search-friendly.
4. They improve flexibility in the modern web page design.
5. They make your website compatible with any web browser since their use is dictated by current W3C standards.

Q7. How do you increase the maintainability of the code?

Ans. The following measures can be followed to increase maintainability in the code:

1. Following a formalized coding standard can increase the scope of modifications within applications.
2. A defined structure should be followed by method, class name and variable. These elements should have human-readable names that describe the intended purpose.
3. Do not complicate logic in order to develop applications with minimum lines of coding. There should be ease of understanding.
4. Use of nested code must be minimized. Use early method return instead of large blocks of code that are contained within conditional.
5. Use methods that do not require external dependencies and that do not mutate external states.
6. Common code must be extracted for sharing methods and utility libraries. This will allow code changes to be made at only one location.
7. Code should be organized and decoupled. Decoupling can be increased through dependency injection while organizing can be done by grouping all models together.
8. Use third-party libraries for minimizing the amount of code that needs to be maintained and tested.
9. Unused code should be removed since it will clarify the actual code that needs maintenance and testing. This will also increase readability.
10. Write self-documenting code rather than relying on inline comments for explaining the logic. This is useful while developing a consumable library or an extensible application.

Q8. What is a development environment?

Ans. It is the collection of tools and processes used for developing the source code of a software or program. The environment automates and facilitates routines that are involved in the creation, testing, debugging, patching, maintenance and updating of the software/program. It should support the process from end to end from development to production servers. 

Q9. Explain the web design workflow.

Ans. The web design workflow has the following fundamental phases:

1. The planning phase is the first stage in which the project objectives are defined as well as the target audience is identified.
2. The implementation phase is the stage where website development including design work and content creation is initiated.
3. The test and launch phase is the final stage of testing web design and content. In this phase, the content is pushed live and visitor data is also collected.

Q10. How does the web design workflow improve the design process?

Ans. This is one of the basic front end developer interview questions. However, it is a fundamental question that you must know. A web design workflow involves step by step website creation from the preparation stage till post-launch of the site.

A defined workflow helps in mapping out timeframes for each task. This will allow you to set achievable project timelines leading to a smoother project lifecycle. Workflow can streamline the process and ensure that there are fewer gaps. The smooth process enhances the productivity of the entire team.

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Q11. How would you integrate multiple stylesheets into the site?

Ans. Multiple stylesheets can be imported into the main stylesheets through Sass. You can refactor CSS in respective stylesheets to prevent duplicated CSS. 

Q12. How do you optimize the resources of your website?

Ans. There are different practices that help in the optimization of your website resources:

1. CDN is a set of web servers that are distributed across different geographical locations. If there is a single server, then the load time will increase due to the increased physical distance between the end-user and the webserver. Using content delivery systems can help in reducing the load time. This will help in the faster delivery of content.
2. Using a faster web host also ensures website optimization. Through shared hosting, website owners can share disk space, CPU and RAM with other servers.
3. Image size should be less in order to reduce the page load time and hence your website will be faster.
4. A fewer number of plugins should be used on the website since more plugins will require more resources to run plugins. It is recommended to delete unnecessary and outdated plugins.
5. More number of JavaScript and CSS files lead to HTTP requests whenever visitors want to access a file on your website. These are treated as individual requests that slow down the website.
6. Website caching is the process of storing the current version of the website on hosting till it is updated. This will prevent the repetitive rendering of the web page.

Q13. What is the difference between graceful degradation and progressive enhancement?

Ans. Both aim towards keeping the product useful for every user. Graceful degradation starts at the level of an ideal user experience and decreases down to a minimum level as per the capabilities of the user agent. It caters to agents that do not support certain features that are used by the baseline. Progressive enhancement starts at the level of minimum user experience and increases as per the capabilities of the user agent. It caters to agents that support more advanced features than by baseline.

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Q14. How does domain sharding work?

Ans. Whenever a user’s browser connects to a web page, it scans the resulting HTML in order to download resources. Usually, the resources are supplied by a single domain. Domain sharding allows the user’s browser to connect with two or more domains to enable simultaneous download of resources required to render a web page. The number of shards used by the web service relies on the number of resources to be downloaded. On average, modern web browsers support 6 concurrent downloads per domain.

Q15. How do you increase the page loading speed?

Ans. There are different methods that can help in improving page load speed:

1. Performance focused hosting solutions offer platforms that facilitate speed. Since these platforms do not offer shared hosting, there is no issue related to the lack of potential resources.
2. Using good quality yet compressed images are significant in reducing page load time. The lesser the load time, the faster is the page speed.
3. It is important to keep fewer redirects on your website since it prolongs HTTP requests and thus, the response process.
4. Browser caching also improve page load speed since the browser can store a lot of information including images, JavaScript as well as stylesheets. This prevents loading the entire page again and again.
5. One should use asynchronous loading since it enables the simultaneous loading of multiple files. This will speed up the page performance.
6. You can increase page load time by minifying the CSS, HTML and JavaScript codes.

Q16. What is Flash of Unstyled Content (FOUC) and how to avoid it?

Ans. Flash of Unstyled Content (FOUC) is a situation that occurs when a web browser shows a web page’s content without having any style information. This issue depends majorly on the architecture of the browser. In order to solve the FOUC method, you can perform the following:

1. By defining the CSS print method to be inline rather than external files.
2. Set the body section:

  and write

After this, body of the web page will stay hidden until the full page and CSS files are loaded. Onload event will turn the body visible once everything is loaded

Q17. What is Web Accessibility?

Ans. Web Accessibility ensures that the web is usable by people who suffer from disabilities. This means keyboard-only users should be able to navigate through your site along with people having hearing and visual difficulties.

Q18. What is ARIA?

Ans. ARIA are attributes that can be added to HTML elements for defining ways to make the web content and applications accessible to disabled users. ARIA is used for fixing accessible issues that cannot be managed with HTML.

We will continue to add relevant front end developer interview questions since there is no limit to improving knowledge. Do check out this article from time to time to see more updates on the topic.

Q19. Define HTML meta tags.

Ans. Meta tags include data related to document title, encoding, character description, etc. These are passed as name/value pairs. They fit inside the head tag of an HTML page and is not displayed on the page but on the browser.