Web Developer Interview Questions and Answers

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Since Full Stack Development has lifted off to be a market worth billions of dollars, it should come as no surprise to you that this creates a vast amount of job openings across the world. As mentioned above, with this comes to a lot of competition, making the interviews a little challenging as well. But nothing to worry about as these Top 45+ Web Development Interview Questions blog is carefully curated by handpicking questions, have the highest probability of occurrence in an interview. Study these diligently and understand how you should approach the questions and effectively answer them.

Basic Web Development Interview Questions for Freshers

1. What is the difference between SOAP and REST?

2. What is the use of a namespace in Web Development?

A namespace is a simple global object that is used to hold methods, properties, and other objects in them. It adds ease of use via modularity, thereby, providing users with the ability to reuse the code and avoid naming conflicts.

3. What are the newly introduced input types in HTML5?

HTML5 has had multiple revamps in the past years, and the addition of input types has made it very easy to work with. Some of these input types are as follows:

• color
• date
• Datetime-local
• email
• month
• number range

Check out our Full Stack Developer Interview Questions video:

4. What are the five elements that support media content in HTML5?

There are five main elements in HTML5 that support media:

• <audio>
• <video>
• <source>
• <embed>
• <track>

5. What is SVG and why is it used?

SVG stands for Scalable Vector Graphics. It is used to display vector-based graphics over the web. The graphical content it can render is based on an XML format. With SVG, the graphical content is of superior quality thereby providing the user with the ability to furnish high-quality images.

6. What is the use of Canvas in HTML?

Canvas was added onto HTML5 to give users the ability to draw graphics on the go, using JavaScript. There are a variety of methods in <canvas> to allow for the drawing of paths, circles, boxes, images, and more.

Next up on this top Web Developer interview questions and answers, let us understand the difference between canvas and SVG.

7. What is the difference between Canvas and SVG?

8. How can page loading time be reduced?

There are many factors that affect the page loading time of a website. However, some methods can be implemented to reduce it drastically. They are given below:

• Reduction in the image size
• Removal of unnecessary widgets
• HTTP compression
• Reduction in lookups
• Minimal redirection and caching

9. What is the use of CORS?

CORS stands for Cross-origin Resource Sharing. It is a mechanism that allows a variety of resources to be requested at a time from a domain that is outside the current request domain.

The next web application interview question comprises an important difference. Check it out below.

10. What is the difference between localStorage and sessionStorage objects?

11. What are some of the new features that are introduced in CSS3?

CSS3 has brought about a lot of changes, making the overall framework more user-friendly and powerful. Some of the features that were added and are very popularly used now are:

• Rounded corners
• Animation
• Custom layout
• Media queries

12. What is Responsive Web Design (RWD) in HTML and CSS?

Responsive Web Design is a concept that is used to create web pages that can scale across multiple resolutions without any loss of information or screen tearing.

It automatically adjusts the structure of the web page based on the device it is viewed on to provide optimal viewing experience.

13. What are some of the types of CSS that are used?

There are three main types of CSS present:

• Inline CSS: Supports the addition of CSS inline, alongside HTML elements
• External CSS: Used to import an external CSS file to the HTML document
• Embedded CSS: Used to add CSS styles by making use of the <style> attribute

14. What is the use of a selector in CSS?

A CSS selector is used with a rule in the inline elements, which require styling. With the help of selectors, it is easy to find and select HTML elements based on factors, such as name, ID, attribute, etc.

15. Can you give an example of using an ID selector in CSS?

The ID selector is used in CSS to point to a target element for usage. It is denoted in the following example:

#example {padding: 20px;}
<p id="SelectorExample">;
...
</p>

16. What is the use of grouping in CSS3?

Grouping is used in CSS3 to give users the ability to reuse and apply the same CSS style element to multiple HTML entities, using just one single declaration statement.

A simple example of grouping is as shown below:

#grouped g, ul { padding-top: 20px; margin: 1; }

17. What is the use of a class selector in CSS?

Class selectors in CSS begin with a “.” (period) key and are followed by the name of the class. It is used to select a statement and modify the style of that element in the corresponding part of the HTML tag.

Consider the following example:

.exampleclass {font-family: TimesNewRomanl; font-size: 20; background: red;}
<div class="sampleclass">;
...
</div>

Next up on these web technologies interview questions, let us understand a little about the use of Webkit.

18. What is the use of Webkit in CSS3?

Webkit is a rendering engine used in CSS3 to display HTML and CSS elements on various web browsers, including Chrome, Safari, and earlier versions of Opera. It provides the necessary functionality for rendering web content and ensuring consistency across different platforms. It is important to note that Webkit is just one of several browser engines, with others including Gecko (used by Mozilla Firefox), Presto (used by older versions of Opera), and EdgeHTML (used by Microsoft Edge prior to its switch to Chromium).

19. What does frontend development entail?

Front-end development refers to the visuals that you may see on the web pages, where end users may interact with some of the web elements. The Front end majorly makes use of HTML, CSS, and JavaScript to create interactive web pages.

20. How does a CDN enhance website performance?

Content Delivery Network, also called CDN, is needed to increase the performance of websites. It hosts the resources of the website on multiple servers and lets the user download the data from the nearest servers available.

21. Define backend in web development.

Operations like user authentication, database interaction, and server-side logic are called the back end of the website. We can use NodeJS and ExpressJS together to implement the backend.

22. What is the purpose of a Doctype in HTML?

The purpose of Doctype declaration in HTML is to tell the browser in what version of HTML the code is written. It also makes sure that the page is displayed in the browser correctly.

23. Explain the use of Semantic HTML.

HTML tags clearly describe the meaning of the tag to both the user as well as the browser.

Examples of non-semantic elements: <div> and <span> – Tell nothing about its content.
Examples of semantic elements: <form>, <table>, and <article> – Clearly define its content.

24. What are the uses of child selectors in CSS?

Child selectors in CSS are powerful tools for targeting specific elements that are direct children of another element. They are denoted by the “greater than” symbol (>) and allow developers to apply styles or perform actions exclusively on immediate child elements. 

Child selectors are useful for creating refined and granular styles, controlling the appearance of specific child elements within a parent container, and achieving more precise CSS targeting.

Next up on this common Web Developer interview questions and answers blog, let us take a look at the intermediate set of questions.

Intermediate Web Developer Interview Questions for Experienced

25. How does CSS3 help in implementing rounded borders easily?

CSS3 has the <border-radius> property that allows elements to be created with nice-looking rounded corners. This can easily be applied to all four sides or as per requirement.

The <border-radius> property has four attributes for four corners:

• <border-top-left-radius>
• <border-top-right-radius>
• <border-bottom-left-radius>
• <border-bottom-right-radius>

26. What is pagination? How can pagination be implemented?

Pagination is a simple sequence of pages on a website. These pages are interconnected and have similar content to display to the users.

A simple example is the page selector on an e-commerce site that allows the users to browse through the products present on multiple pages rather than scrolling up and down on one single page.

It can easily be implemented in CSS3 using the following code:

<div class="main_container">
<div class="pagination">
<ul>
<li><a href="#"></a></li>
<li><a href="#"></a></li>
<li class="active"><a href="#"></a></li>
<li><a href="#"></a></li>
</ul>
</div>
</div>

27. What are the components of the CSS box model?

The CSS box model is used to represent an entity that encloses all of the HTML content into a box or a button element.

There are four components:

1. Border: Denotes the padding and content around the border
2. Content: Refers to the actual content to be displayed
3. Margin: Refers to the top layer of the box element
4. Padding: Defines the empty space around the element

28. What are some of the properties of transitions in CSS3?

Transitions in CSS3 are easy to use, and they provide users with rapid and efficient animation effects.

The four main properties present in the transitions are:

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

29. What is the use of pseudo-classes in CSS?

Pseudo-classes are used as a popular technique in CSS to change the style of an element when this element changes its state.

There are numerous examples of when you use a pseudo-class:

• For the style change when the mouse moves over the element
• For out-of-focus animations
• For providing styles for external links

30. What is the use of media queries in CSS3?

Media queries are used to define styles in CSS, which are responsive based on a variety of shapes and sizes of the viewing window.

They are used to adjust the following entities:

• Height
• Width
• Viewport
• Resolution
• Orientation

31. Why is float used in CSS?

Float is a popular property in CSS to control the layout and position of an element on a web page.

Any element can be placed on the web page as per requirement. Consider the following example:

div  { float: right; }

Here, the contents of div will be placed on the right side of the screen.

32. What is z-index in CSS?

Z-index is a property in CSS that is used to define the order of elements on a web page. It works on the basis of order indices, where a higher-order element will appear before a lower-order element.

It only applies to elements that are positioned, i.e., those elements having the position attribute compulsorily.

Consider the following example:

div {
position: fixed;
left: 15px;
top: 20px;
z-index: -1;
}

33. Why are external style sheets preferred?

External style sheets provide an ample amount of advantages to developers. Some of the benefits are as follows:

• Classes can be reused any number of times.
• They allow for the style control of multiple documents through a single file.
• Selectors and grouping can be used to apply styles easily.

34. What is the meaning of long polling in Web Development?

Long polling is a development pattern that is used to emulate a data push operation from a server to a client machine.

When long polling is operational, the client sends in a request to the server, and the data is pushed. The connection will timeout only when the data is sent to the client or after the timeout criteria are met.

35. What are some of the Web Development technologies that you know?

This question is very common in a Web Development interview. The answer is based on your learning, experience, and proficiency in this field. However, a good Web Developer will have profound working skills in any of the following technologies:

• HTML
• CSS
• JavaScript
• SQL
• Python
• PHP

36. What is the difference between cookies and local storage?

In the next set of interview questions for web developers, we have a very important question regarding HTML and XHTML.

37. What is the difference between XHTML and HTML?

38. What are the various data types present in JavaScript?

JavaScript supports the following data types:

• Boolean
• Number
• Object
• Undefined
• Null
• String
• Function

39. What is RESTful API design?

RESTful APIs are web services used to send data between a client and a server as HTTP requests. The server is not able to remember them, as the requests are stateless. This makes RESTful APIs adaptable and flexible.

40. Explain the concept of state in web applications, and how does it enhance the user experience compared to static web pages?

State means saving information about the user as they use the site. This could be things like items in their shopping cart or their login status. The state allows the website to be dynamic. It enables personalized experiences, like showing someone their account settings page after they log in. Without using state, web pages would just be static documents that are the same for every visitor. The state makes the web feel more like an interactive application. 

41. What is a web application framework?

 A web framework, also called WAF, is a pre-built set of libraries that help the developer create the website. It has codes that are common for different websites, such as authentication. It provides the code for the comma part and allows the developer to focus on the unique part of the website.

42. What are WebSockets used for?

With the help of WebSockets, you can enable real-time, event-driven communication between a client and server. WebSockets allow bi-directional communication, meaning the client and server can send data to each other at any period.

43. How do CSS preprocessors enhance CSS coding?

CSS preprocessors like SASS and LESS extend regular CSS with extra features. They add variables for reusable values, nesting to organize code and functions for complex operations. These improvements make writing CSS more efficient, reusable, and maintainable. The preprocessor CSS gets compiled into normal CSS that browsers understand.

44. How can styles or classes be changed in elements using JavaScript?

JavaScript can be used to easily modify classes and styles in an element by making use of the following syntax:

Modify styles: document.getElementById(“input”).style.fontSize = “10”;
Modify class: document.getElementById(“button”).className = “classname”;

Next up on this top Web Development interview questions and answers blog, let us take a look at the advanced set of questions.

Advanced Web Development Interview Questions

The following will cover the senior web developer interview questions but we suggest you go through them even if you are a fresher or an intermediate web developer candidate.

45. What are the types of popup boxes present in JavaScript?

There are three types of dialog boxes, which are used in JavaScript:

• Alert: Presents users with a message and an ‘Ok’ button
• Confirm: Gives the users a window with ‘Ok’ and ‘Cancel’ buttons
• Prompt: Shows the user input, alongside ‘Ok’ and ‘Cancel’ buttons

46. What is the difference between <window.onload> and <onDocumentReady>?

The <window.onload> event is not called until a page is completely loaded with the entire styling from CSS and images. The event does add a bit of delay when rendering a web page. With the <onDocumentReady> event, it will wait only till the DOM is initialized and will begin the event action. This ensures to reduce any delays in actions.

47. How is type conversion handled in JavaScript?

JavaScript supports automatic type conversion. Since it is weakly typed, you can pass a function as an argument into another function easily.

This ensures that there are no errors or data type-associated warnings as values get converted to the required data type automatically.

48. What is the meaning of the scope of a variable in JavaScript?

Scope refers to the accessibility of functions and underlying variables in the running environment. There are two scopes supported in JavaScript:

• Local scope: Here, values and functions declared inside the same function can only be accessed within that function and not outside it. Consider the following example:

// Code present here cannot use localVariable
function myFunction() {
var localVariable = "This is a local variable";
// Code present here can use localVariable
}

• Global scope:  If a variable is declared as global, it can be accessed from anywhere in the application. Consider the following example:

var globalVariable = "This is a Global variable";
// Code present here can use globalVariable
function myFunction() {
// Code present here can also use globalVariable
}

49. How are comments used in JavaScript?

JavaScript supports two types of comment insertion in the code. Single-line comments and multi-line comments.

• Single-line comment: “//” is used for single-line comment insertion

Example:

//This is a single-line comment

• Multi-line comment: “/* */” is used to add multi-line comments

Example:

/* This
is a
multi-line
comment*/

Coming to the next set of interview questions for web developers, here is a common question for JavaScript.

50. What are undefined and undeclared variables in JavaScript?

Variables that have been declared already but not initialized are known as undefined variables.

On the other hand, if a variable is being used in a program without being declared, then it is considered an undeclared variable.

Consider the following example:

var undefVar;
alert(undefVar); // undefined variable
alert(notDeclared); // accessing an undeclared variable

51. What is the method used to submit forms in JavaScript?

Forms can be submitted easily in JavaScript by calling the following method:

document.forms[0].submit();

Here, the ‘0’ denotes the index of the form.

52. Why is <this> keyword used a lot in JavaScript?

The <this> keyword is used to access the current object present in a program. This object resides inside a method, and the keyword is used for referencing the corresponding variable or the object.

53. What is the use of the <defer> attribute in JavaScript?

The attribute is used as a boolean type attribute. It is used to delay the execution of the JavaScript code on a web page until the parser completely loads and initializes the page.

54. How can you prioritize SEO, maintainability, performance, and security in a web application?

This is a commonly asked question in a Web Development interview. Here, the interviewer is trying to assess your understanding of the working environment in the firm you’ve applied for.

If it is a large firm, then security will get higher priority over SEO. Whereas, if it is a publication firm, SEO gets the preference. A little groundwork about the company should help you answer this question.

55. What is the result if a jQuery Event Handler returns false?

If a jQuery event handler returns false, it prevents the default behavior of the event and stops the event from propagating further. This can be used to cancel actions like form submission or link navigation when certain conditions are not met.

56. What is the use of the each() function in jQuery?

The each() function in jQuery is used to iterate over a collection of elements and perform a specified action for each element. It simplifies the process of applying operations or modifications to multiple elements in an efficient and concise manner.

57. What is Pair Programming?

Pair programming is a collaborative software development approach in which two programmers work together on the same task. One person, known as the “driver,” writes the code while the other, called the “observer” or “navigator,” actively reviews the code being written. They continuously switch roles, fostering teamwork, knowledge sharing, and code quality.

58. What is the use of the $() function in jQuery?

The $() function in jQuery is used for selecting and manipulating HTML elements. It provides a convenient way to modify attributes, styles, content, and apply event handlers to selected elements using a concise and intuitive syntax.

59. What are the advantages of using a Content Delivery Network (CDN) in jQuery?

CDNs are widely used in jQuery as they offer an ample number of advantages for users.

• CDNs cause a significant reduction in the load for the server.
• They provide large amounts of savings in the bandwidth.
• jQuery frameworks load faster due to optimizations.
• CDNs have a caching ability that adds to quicker load times.

60. What are the types of CDNs supported in jQuery?

There are two widely used CDNs with jQuery:

• Microsoft: Used to load from jQuery AJAX CDN
• Google: Used to load jQuery from the Google Libraries API

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61. Explain microservices architecture.

Microservice architecture splits up an application into smaller, self-contained services instead of one large application. Each microservice focuses on a specific capability and can be developed and updated independently. This modular approach makes applications easier to develop, maintain, and scale.

62. What is Continuous Integration (CI)?

Continuous Integration is a coding practice where developers regularly merge code changes into a shared repository. Automated builds and tests run with each code change to catch errors early. This frequent code integration and testing helps improve software quality and speed up delivery.

63. How does Server-Side Rendering (SSR) benefit SEO?

With Server-Side Rendering (SSR), web pages are generated on the server before being sent to the browser. This makes content immediately available to search engine crawlers for indexing, improving SEO. SSR ensures search engines can fully access and read web page content.

64. Describe the significance of Git in web development.

Git tracks all changes made to code and allows multiple developers to work together without overwriting each other’s changes. It coordinates collaboration by managing code history and merging updated code from different contributors. Git enables distributed teams to develop software efficiently by versioning source code and facilitating parallel workstreams.

65. How does the BEM methodology benefit CSS coding?

BEM (Block Element Modifier) is a way to structure CSS class names. It helps organize code by naming classes after the HTML components they style. This reflects the relationship between structure and appearance. BEM improves CSS readability, maintenance, and scalability by making class names more meaningful.

Download the Web Developer Interview Questions PDF to prepare for interviews offline.

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