Web Developer Interview questions 2021 [updated]

Web Developer Interview questions 2021 [updated] – most frequently asked Web Developer interview questions and their best possible answers.

Table of Contents

1) Explain the key responsibilities of a Web Developer?

Key responsibilities of a web developer include:

Program testing and debugging web applications
Design, develop, test, and deploy applications.
Updating sites for optimized server performance.
Coordination with designers and programmers to develop projects.
Fixing bugs, troubleshooting, and resolving issues
Predicting and implementing periodic tests in case of system failure.
Developing design patterns for web program optimization.
Support and assist with best practices for website management.
Take ownership of code throughout staging, development, testing, and deployment of the project in production.

2) What are the prerequisites of being a web developer?

A beginner web developer is expected to have a fundamental knowledge of HTML, CSS, JavaScript, and other aspects like jQuery, SQL, and some other scripting languages. An experienced web developer is expected to have all the given aspects and great knowledge of design patterns.

3) Enlist the advantages of HTTP/2 as compared with HTTP 1.1/.

The advantages are:

Data compression through HTTP headers.
Ease of logical server push technology.
Prioritizing a request.
Page element loading through TCP connection.

4) What is CORA? Why is it so important?

Cross-Origin Resource Sharing (CORS) is defined as the browser mechanism that involves controlled resources access granted outside the given domain. It can enable a web page to access the resource with a different domain. It is a relaxation of some policies associated with browsers implemented on the same origin.

CORS is important because it follows the same-origin policy by channeling XMLHttpRequest and fetching JavaScript to make URL calls in the same location where the script is running. Without CORS, there will be restrictions in accessing some critical resources that power the web.

5) What is ETag, and how does it function?

An ETag is termed an opaque identifier that is usually allocated by the webserver. It is primarily used within the same version of the resources provided in the URL. ETag is an important part of HTTP and is responsible for reading client requests to notify whether to send the file (HTTP 200) or inform the client through a local copy (HTTP 304).

6) Enlist some of the latest form elements of HTML5.

: specifies input controls option list.

: encryption key generator.

: result generator of expression.

: max value directional to 100%.

: provides a range for displaying values within a range

7) How to integrate different stylesheets into a website?

It depends on the factor of how the site is laid out. However, for the most efficient performance, one file can be used with styles.css. If you want to change any style, open up the styles.css file, and in the relevant section, you can modify CSS. You can also link your HTML file through the below command.

8) Enlist some tricks to reduce the load time of a web application.

Some of the most popular hacks to reduce load time are:

Save the images as a compressed file so that image size can be optimized to screen resolution.
Remove every JavaScript file to reduce mobile data.
Minify and combine CSS and JS to call them in the footer.
Switch to asynchronous JavaScript.

9) What is the correct way to include JavaScript into your HTML?

The most effective way to include JavaScript in your HTML is by referring to event handlers or including inline code.

10) What are some of the pop-up boxes available in JavaScript? Explain them.

There are usually three types of boxes available in JavaScript. They are:

ALERT displays a message with an OK button.

CONFIRM: displays a confirmation window with OK and Cancel buttons.

PROMPT: displays a pop-up dialog box seeking user inputs followed by confirmation buttons.

11) Define Scope in JavaScript and name different types of Scopes.

The scope is usually defined to felicitate the accessibility of variables and methods(functions) in applications. There are two types of Scopes in JavaScript: Local and Global.

12) What is the difference between ‘==’ and ‘===’ operators?

Although both of the operators belong to the comparison operator category, the ‘==’ operator checks the given values, whereas the ‘===’ behaves like an equality operator and checks both the value and their type.

13) What is the difference between and in HTML?

With frames, you can display more than one document in the browser window. Also, the tag can be used to declare a separate window within a frameset.

With division, you can define a section in an HTML document and block elements within certain formats and styles. Division can serve local content, although the content is not independent of the page constituent.

14) State how HTML differs from XHTML?

Although, HTML and XHTML are known for writing web pages but HTML is extended version from SGML tagging. On the other hand, XHTML is just an application of markup language called Extensible Markup Language.

However, HTML usually has three components, i.e., start and end tag, elemental attribute tags, and content in text and graphics. In contrast, XHTML includes a single root element that constitutes only lower case elements whose values assigned should be nested and closed. They also need to round with quotation marks. Therefore, it comes down to a conclusion that XHTML is more expressive than HTML is more framed.

15) What is Node Package Manager or NPM?

NPM is a package manager for JavaScript. NPM is designed to put modules intact so that nodes when the need can find them. It is designed to maintain and serve conflicts arising in dependencies. It is mostly used to install programs, configure them, publish and develop them using the intact resources in the modules.

16) What is Webpack?

Webpack in JavaScript is generally a static module bundler designed to bundle JS files in the browser and check their usage. It dynamically puts various files, assets, images, and fonts in a graph of dependency. It enables you to use the required () method to point to the files and figure out how they will be processed in the final bundle of JavaScript. Initially, a webpack slows down when used initially, but the speed eventually picks when correctly used.

17) What is Document Object Model (DOM)?

DOM is defined as the interface channeling cross-platform programming and is primarily used to represent HTML and XML documents in nodes and objects. In simple words, DOM defines the way of manipulating the logical structure of the documents and how they are accessed. It can enable developers to modify, create, or remove the document structure, content, and style used.

Moreover, whenever a document is displayed in the browser, it contains the combined style because it automatically converts the styling components like CSS into DOM. The DOM combines these styling components in the content of the document.

18) How can you effectively handle type conversion in JavaScript?

Since JavaScript is a weakly typed language, it automatically converts the data to that type to which an operator or statement expects a particular data type to be converted. JavaScript supports automatic type conversion, and it is the only way to handle different types of type conversion techniques for JavaScript developers.

19) What is CDN in jQuery? What are the advantages of it?

A Content Delivery Network (CDN) is an interconnection of computer systems globally, and it contains cache files for users to access. It enables users to access the content quite fast by duplicating or caching the content optimally stored on multiple servers and then directing them according to the proximity. Some of the advantages of using CDN are as follows:

Faster delivery of content.
Less load frequency across pages.
Low latency and infatuation rate with little packet loss.
Highest bandwidth-saving ability.
Best analytics usage report.
Secure content storage.

20) What is W3C? Why is it considered important?

W3C abbreviates for World Web Consortium. It is an international community of developers and teams that emphasize standardizing, correcting, and developing the web across global users and defining best practices. The World Wide Web (WWW) is a standard set by W3C and has different member organizations that control it through various IT-related projects. W3C is considered important because it leads the World Wide Web to its greatest potential and ensures its growth in the long term.

Moreover, W3C mainly focuses on developing certain constraints and guidelines for critical web assets like HTML and CSS programming. It also focuses on XML technology, web devices, authority tools, and web browsing experience. It helps web developers to write scalable code and run it everywhere. A web developer is expected to enforce these open standards to ensure that web content is accessible to all audiences globally and delivers a great user experience.

21) What is Ajax? Enlist some of its utilities.

Asynchronous JavaScript XML or AJAX enables different applications to transport data to and from a server asynchronously without refreshing the web page. It simply ensures that some parts of the page are automatically updated without reloading the entire page to fetch new resources on the same page. AJAX can be implemented anywhere in the web application where small chunks of information can be retrieved or saved. This technology helps developers to create faster, efficient and interactive web applications. Some of the utilities or benefits of AJAX are:

Faster callback performance.
Allows asynchronous calls to a web server.
Improves web performance and usability.
User-friendly, easy to understand, and implement.

22) What are some of the latest features of CSS3?

CSS3 has brought tremendous changes ranging from making a more user-friendly framework and has become powerful. Some of the latest features added CSS3 are:

Animation enabled.
Offers rounded corners to objects.
Custom layout.
Efficient placement of media queries.

23) What is Responsive Web Design (RWD)?

Responsive web design is generally a concept of creating web pages that can be easily scaled across various resolutions without losing any information or screen tearing. The main concept of responsive web design is to deliver the structure of the web page that can be automatically adjusted across various platforms and devices with an optimal viewing experience.

24) Enlist some of the types of CSS used.

There are mainly three types of CSS used: They are:

Inline CSS: Supports additional CSS inline with HTML elements grouped.

External CSS: Used to import an external CSS file to the current HTML document.

Embedded CSS: Uses

25) Why is the selector used in CSS?

The selector in CSS is used in styling with the rule of the inline elements. It is easy to choose and select HTML elements with selector usage based on factors including attributes, ID, and name.

26) What are CSS box model components?

The CSS box model components represent an entity under which HTML content is enclosed, like a box or a button element. Some of its components are:

Border: Denotes the content and padding around borders.

Content: Focuses on the actual displaying content.

Padding: Portrays space around the element.

Margin: Focused on the top layer of the box element.

27) What are some of the CSS3 transition properties?

Transition in CSS3 is very easy to use, and it provides rapid effects in terms of animation. Some of the main transition properties of CSS3 are:

transition-delay
transition-duration
transition-property
transition-timing-function

28) Why do we use pseudo-classes in CSS?

Pseudo-classes in CSS are popular ways to change the styling elements in CSS by changing their states. There are plenty of instances where pseudo-classes are used. They are:

Hovering the mouse over an element to change the style.
Providing out-of-focus animations.
Providing external link styles.

29) Why are media queries used in CSS3?

Media queries in CSS are used to define different media asset queries that are responsive and come in different varieties of shapes and sizes depending upon the viewer’s window. The entities may include height, width, viewport, resolution, orientation, etc.

30) What are GET and POST? Explain what the difference between getting and Post is?

A GET request is generally used in the instances like AJAX calls to an API. GET requests are limited and secure. The user can easily view them if they have the URL.

A POST request is typically used to store data in a database submitted through a form. POST requests are more secure than getting requests. They have two steps to utilize the resource and remain hidden from the user.

31) Why do we use DOCTYPE in HTML?

DOCTYPE in HTML denotes the instruction given to a web browser regarding the version of markup language. The web browsers understand the Document Type Definition (DTD) from the HTML document and provide some markup language rules so that the web browser can easily interpret the content correctly.

32) What is lazy loading?

Lazy loading is defined as a design pattern used in computer programming to delay the object initialization until a certain required period. Lazy loading is time-constrained since the code gets loaded when the user needs it. For instance, a button on a page directs to a different layout when it is clicked. Hence, there is no need for code loading for the initial layout. Besides, lazy loading contributes to the overall performance of a program if properly utilized.

33) What is Event Bubbling?

Event bubbling is defined as the type of event propagation where the target element is first triggered. The triggering causes all the events of the child node to pass them to the parent node. The main reason for doing event bubbling is to get the speed since the code needs to traverse the DOM tree only once.

34) What is a Closure?

A closure is termed as a sequence of function bundling referencing the enclosing state. It allows you to access the scope of external function from an inner function. Whenever another function renders a function, this is when the concept of closure becomes more relevant. Thus, the rendered function will have access to the variable not in the global scope but can individually access their closure.

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I hope my interview experience will be helpful for you. Best of luck with your job interview.

Thanks for reading, and enjoy coding ❤.

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