Javarevisited: Top 20 Web Development Interview Questions and Answers

Hello guys, if you are preparing for web developer job interview and looking for frequently asked web development interview questions then you have come to the right place. Earlier, I have not just shared HTML Interview Question, CSS Interview Questions, and JavaScript Interview Questions, but also question from popular Frontend frameworks like React and Angular, and in this article, I am going to share common web development interview questions for 3 to 5 years experienced professionals. If you have worked as a web developer or created a couple of web projects then you may know answers of all of these questions but if you struggle to answer them then you can always go back and join any of these best web development courses to learn and revise key web development concepts.

If you are looking to land a job in the software industry, web development is something that you should definitely have in your toolbox. Basically, web development refers to everything from building, creating, and maintaining websites.

As a web developer, you should also be proficient in designing, programming, as well as database management. The world of web development can be classified into frontend development and backend development.

The front end is that part of the website that the user directly interacts with. It is also known as the client-side of the application.

Backend development basically deals with the server-side of a website. Users cannot interact with this part of a website. What this means is that this piece of software does not come in direct contact with the users. In this article, I have shared both frontend and backend interview questions.

20 Web Development Interview Questions with Answers

It can be tough when you are preparing for an interview. Especially if you really want the job. Trust me, we have all been there. And that is why this article is going to help you massively. The questions in this article will help you master the field of web development and land your dream job.

1. What is difference between == and === operator in JavaScript? (answer)

This is one of the most popular JavaScript interview question and surprisingly many web developer doesn't know answer of this. While both == (double equals) and === (triple equals) operator are used to check whether two variables are equal or not there is a subtle difference between them.

The == (double equal to) variable only checks value and not the type but === (strict equality operator) checks both value and type of variables while comparing them.

This means if you have two variables, 1 and "1" where first is numeric and second is string then == will return true because both has same value but === will return false because even though the value is same their type is not same. You can also see my earlier article about == vs === in JavaScritp for more examples.

2. What is difference between let, const, and var in JavaScript? (answer)

Well, all three keywords are used to declare variables in JavaScript but var is the one which is there from start while let and const keywords are added in ES7. The key difference between these two sets of keyword is the scope and whether you can update and re-declare them.

The var keyword can be used to declare both local and global variables, for example a var variable declared outside a function will have global scope and available everywhere while the variable declared inside the function will be only available in function or have local scope.

On the other hand, let and const are block scoped. This means any variable declared using let will only be available in the block they are declared. That's why let is now preferred over var for declaring local variables in JavaScript code.

Also the variables declared with var can be updated and re-declared while variables declared with let keyword can be updated but cannot be re-declared. In the case of const, the variable cannot be updated or re-declared as its treated as constant.

Another key difference between variables declared using let and var keyword in JavaScript is that var variables are initialized as undefined, the let variables is not initialized. So if you try to use a let variable before declaration, you'll get a Reference Error. That's all about the difference between let, var and const variable in JavaScript.

Also, here is a nice table summarizing scope of var, let, and const variables:

If you want to learn more You can also my earlier blog post about let vs const vs var in JavaScript for more discussion and examples.

3. What is Namespacing in JavaScript?

The namespace basically refers to a container name that can be used for storing classes, functions, and variables. This can also be repeated in other namespaces by invoking the same name without any error.

4. What can you do to reduce page loading time?

You can use any of the following tricks to reduce the loading time of web pages:

Reducing the image size
Removing unnecessary widgets
Avoiding multiple redirects
Reducing lookups
Checking the current speed of the website
Cleaning the web code

5. What can you tell us about CORS?

CORS stands for Cross-Origin Resource Sharing. It is a browser mechanism that can be used for allowing controlled access to resources that are located outside a given domain.

6. What are some of the advantages of using HTTP 2.0?

HTTP 2.0 offer higher loading speeds and automatic prioritization. It can also be used for improving web positioning as well as decreasing broadband consumption and faster presentation.

7. What are some of the new form elements introduced in HTML 5?

Some of the new forms introduced in HTML 5 are:

<keygen>, which generates an encryption key
<progress>, which heads in the direction of max value
<meter>, which displays a general value within a range
<output>, which provides an output
<datalist>, which specifies a list of options

8. What is the most efficient way to integrate stylesheets into a website?

The best way would be by using just one file named styles.css. You can change the style by scrolling to find the relevant section and modifying the CSS.

Top 20 Web Development Interview Questions with Answer with 3 to 5 years experienced

9. What can you tell us about the default border size in Canvas?

The most important thing to note here is that there is no default border size in Canvas. The border size can be adjusted by modifying CSS.

10. What is your idea of a perfect development environment?

When you answer this question, you should definitely mention that you are flexible enough to work in any environment. You should be able to adapt to any environment by making use of your core skills.

frontend and backend interview questions with answers

11. What are some of the new APIs provided by HTML5?

The new APIs present on HTML5 is Text track API, Media API, Data transfer API, Application Cache API, User Interaction API, Command API, Constraint Validation API, and History API.

12. What can you tell us about the difference between null value and undefined value in JavaScript?

An undefined value in JavaScript basically means that a variable has been declared but has not yet been assigned a value. In contrast, a null value refers to an assignment value. You need to understand that undefined is a type while null is an object.

13. What are some of the web technologies that you are proficient in?

You should basically have expert skills in HTML5, CSS3, and JavaScript. You should also have some working knowledge of some other technologies like APIs, popular frameworks, and database management.

14. What are the different types of pop-up boxes available in JavaScript?

There are three different types of pop-up boxes available in JavaScript.

The Alert box simply displays a message with an OK button.
The Confirm box shows a confirmation message window with an OK and a Cancel button.
The Prompt box asks for user input followed by confirmation buttons.

JavaScript interview questions for web developers

15. What can you tell us about Scopes in JavaScript? What are the different types of Scopes?

The scope can be used for defining the accessibility of functions and variables that are present in a function. There are two types of scopes:

Local - This includes variables that are defined inside a function
Global - This includes variables that are defined outside of a function.

16. What mechanism can you use in JavaScript for detecting the operating system on a client machine?

You can use the JavaScript property navigator,appVersion for detecting the operating system on a client machine.

17. Can you use Git for pushing real changes on a website?

Git can be used for streamlining live updates on websites. This can be done by making use of a post-receive hook. You will be able to copy updates from the remote server repository and update them onto the live website.

Web Development Interview Questions with Answer with 1 to 5 years experienced

18. What are some of the web development tools?

Here are a couple of popular web development tools you can learn:

CodeKit can be used for minimizing and combining JavaScript.
GitHub can be used for working together with a team.
CodePen can be used for deploying websites and building test cases.
JS can be used for structuring web applications.
Grunt can be used for automating repetitive tasks.

I have also shared more tools on my earlier articles 10 Web development tools every developer should learn, you can also check that article if you need more tools.

19. How can you optimize your website's loading time?

You can do this by implementing caching and minifying CSS, HTML, and JavaScript codes.

20. What can you tell us about HTTP/3?

It is the new third-generation HTTP standard that was made available in 2019. It offers a fast, secure, and reliable connection.

21. How can Canvas be used in HTML?

The Canvas element can be used for drawing graphics using JavaScript. It can also be used for drawing graphs, combining photos, and creating basic animations.

23 . What is the basic difference between Canvas and SVG?

Canvas is basically an HTML5 element that can be used for drawing graphics quickly with the help of JavaScript. SVG can be used for displaying vector-based graphics on the web.

Conclusion

That's all about the popular web development interview questions and answers for people with 3 to 5 years experienced. The questions in this article will help you become an expert web developer and allow you to land your dream software job. If you liked this list of the Top 20 Web Development Interview Questions, feel free to share it with your friends and family.

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Javarevisited

Top 20 Web Development Interview Questions and Answers