Top 20 Interview Questions for Web Developer Jobs

1024 599 tony

Top 20 Interview Questions for Web Developer Jobs

Appearing in an interview can be intimidating if you are undercooked and underprepared, and as discussions over at reveal, this could lead to you feeling overwhelmed and losing confidence in front of the interviewer, which will damage your chances of getting the job. If you want to be successful in w web developer interview, you need to prepare for the commonly-asked web developer interview questions, and this article will look to help you with that by listing 20 such questions and their answers.

What are the key responsibilities of a web developer?

As outlined over at, the key responsibilities of a web developer include:

Program, test, and debug all web applications

Design, develop, test, and deploy web applications

Uploading sites onto the server and registering them with different search engines

Coordinate with other designers and programmers to develop web projects

Assume ownership of code through staging, development, testing, and production

Fix bugs, troubleshoot, and resolve problems

Support and assist in the upkeep and maintenance of websites

Develop appropriate code structures to solve specific tasks

In case of system failure, initiate periodic testing and implement contingency plans

What programming languages should a web developer know?

According to, a good web developer should know:







What is CORS and how does it work?

Cross-Origin Resource Sharing (CORS) is a mechanism that enables many resources like JavaScript, fonts, and many others, on a web page to be requested from another domain outside the domain from which the resource originated. It is a mechanism supported in HTML 5 that manages XMLHttpRequest access to a different domain, with more on this to be found over at

What are the advantages of HTTP/2 compared to HTTP/1.1?

The advantages of HTTP/2 compared to HTTP/1.1 are:

HTTP headers data compression

Server push technologies

Over a single TCP connection parallel loading of page elements

Prioritization of request.

What is an ETag and how does it work?

An ETag is an opaque identifier allocated by a web server to a specific version of a resource found at a URL. It is part of HTTP, the protocol for the world wide web, and when the server reads the ETag from client request, the server can then tell whether to send the file (HTTP 200) or tell the client just to use their local copy (HTTP 304).

What is long polling?

Long polling is a web application development pattern used to emulate pushing data from the server to the client. When used, the client sends a request to the server, and the connection remains intact until the server is ready to send data to the client. The connection will be closed only after the data is sent back to the client or connection timeout occurs, as articulated over at

What is DTD (Document Type Declaration)? Mention the difference between CDATA and PCDATA in DTD.

DTD (Document Type Definition) defines the structure, legal elements, and attributes of an XML document as per

PCDATA – A PCDATA is a parsed Character Data. XML parsers usually parse all the text in an XML document.

CDATA – While CDATA is an Unparsed Character Data, and the term CDATA is used to describe text that should not be parsed by the XML parser.

What are some of the tips you can use to reduce the load time of a web application that you have written

As explained over at, this is a common question. To decrease the load time of a web application, the following tips will come in handy:

Optimize images to no longer than screen resolution and save it as a compressed file

Eliminate all JavaScript files to reduce the amount of transferable data

Defer or Asynch JS Files

Combine and Minify all CSS and JS and call them in the footer

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

The correct way to include JavaScript into your HTML is by using inline event handlers or inline code.

How can you make a form element’s background color change when the user is entering text in CSS? Does this work in all browsers?

Yes, you can change the default look of form elements by styling their HTML tags: input, select, and text area but it won’t work for all browsers.

List out the new APIs provided by HTML 5 standards

As outlined over at, HTML 5 comes with several new APIs:

Text track API

User Interaction

Application Cache API

Command API

Data Transfer API

Constraint Validation API

Media API

History API

What is Webpack?

Webpack is a fixed module bundler for JavaScript. It is a construction tool that is used to bunch JavaScript files for usage in a browser. It puts the packs of assets, such as codes, images, fonts, and files in a dependency graph, and facilitates you to employ require() in your source code to peak to local files, like images, and decide how they are processed in the ending JavaScript bundle as explained over at

What is DOM?

Document Object Model (DOM) is a cross-platform programming border that symbolizes HTML and XML documents as nodes and objects. It defines the logical arrangement of records and the method the documents are accessed and manipulated. According to discussions over at, DOM enables programmers to generate, modify, and delete the document’s construction, style, and content. When a form is displayed on a browser, the scope of the document must survive combined with its method information.

What is Npm?

Npm refers to Node Package Manager and it is a wrap-up manager for JavaScript. Npm puts modules in position so that node can find them. It also manages dependence conflicts. It is used to issue, discover, install, and expand node programs.

What is type coercion in JavaScript?

Type coercion refers to the change of a value from one type to another with comparable content. In case the performance of the implicit exchange is not sure, then the constructors of a data kind can be used to convert any value to that data type.

How can you refer to a CSS file on the web page?

You can refer to the .CSS file in the webpage by using the <link> tag as articulated over at It should be kept between <head></head>tag. For example, <linkref=”/css/mystyle.css”type=”text/css” rel=stylesheet”/>

What is progressive rendering in HTML?

Progressive rendering is a method with which you can in succession update small parts of the complete webpage and stream it to the client in parts without waiting for the complete page to be rendered. It means that when you start depicting the serious content on the server, you can flow it to the client without waiting for non-vital content to be rendered, with more on this to be found over at

In HTML, what tag can be used for a multi-line text input control?

For multi-line text contribution control, you can use the “text area tag”, with a more detailed illustration of the same to be found at

What is Namespacing in JavaScript?

It is usually not a good practice to use global variables in programming languages including JavaScript. However, you may have to use global variables sometimes, which is why JavaScript introduces the concept of namespacing which ties down a part of the code and registers it with a unique name. The namespace is nothing more than a container name where we hold classes, functions, and variables that can be repeated with the same name in other namespaces without involving an error.

How do you take into account SEO, maintainability, UX, performance, and security when you are building a web application?

When answering this question, explain how you prioritize your actions as per the requirements of the organization. If the organization you are interviewing at handles vital data, then security will be your top priority. If it is a medium-sized online business, SEO and UX might be your top priority, and so on.

These are some of the questions you can expect when interviewing for a web developer job, with more questions and their answers to be found over at the highly-regarded and

Leave a Reply

Your email address will not be published.