Crack the top 30+ HTML interview questions and answers

Aug 05, 2020 - 14 min read
Aaron Xie
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Frontend development continues to rise in popularity as more companies become web-oriented. As new technologies continue to innovate the frontend space, companies are on the lookout for specialized frontend developers.

When you’re preparing for your frontend development interview, you’ll be brushing up on JavaScript and the latest frameworks, but it’s important that you don’t forget about HTML, one of the foundational building blocks to web development.

You may think that you don’t need to review your HTML concepts, but during the interview, you face nuanced questions that you need to prepare for beforehand. Today, we’ll break down 30+ popular HTML interview questions to refresh your understanding of HTML before your next frontend interview.

Today we’ll cover the following:



Succeed in your frontend interview.

Check out this resource to strategically prepare for your frontend coding interviews.

HTML for Front-end Interviews



Introduction to frontend interviews

Technical front-end interviews can be incredibly difficult. In almost every scenario, HTML will not be the only concept that you are being interviewed on. You will be tested on your understanding of all components of web development, but HTML is essential to your success. HTML is the first step when it comes to preparing for coding interviews, as it is the foundation of web dev as a whole.

Though we will be focusing on HTML today, you will need to know other concepts. Refresh your understanding of. the following frontend concepts:

  • General networking knowledge: technologies, architectures, and paradigms such as HTTP requests, web security, REST vs RPC, and more

  • CSS: language basics and advanced add-ons like SASS preprocessors

  • JavaScript language: advanced JavaScript including concepts like callbacks and promises

  • Design patterns: structural, creational, behavioral, and more

  • Frameworks and libraries: you’ll want to speak to your personal experience with .js frameworks. and libraries

  • Data structures: Linked Lists, Hash tables, Trees, Graphs (know search algorithms), and more

  • Algorithms: study the Big-O complexity of each as you prepare

  • Web performance: the performance implications of your code, such as critical rendering path. service workers, image optimization, rendering performance, and more


Types of HTML & frontend interview questions

Before studying questions, it’s important to understand that coding questions fall into common patterns. Understanding those patterns makes it easier to come up with a solution quickly. The interview questions broadly fall into the following categories:

Skills demo. These aim to see you in action to assess the efficiency of your workflow.

Ability to adapt. These questions judge your knowledge of the current tech trends and how well you can work with new technologies. For instance, you may be asked about what kinds of blogs you like to read or influential Twitter developers you follow.

Knowledge. Questions to test your understanding of the industry

Personality. Gauging how well you fit the company’s values

Open-ended questions. These questions may gauge anything about your skills, interest in web development, history with programming, and more, such as,

  • What got you excited about web development?
  • What is front-end web development, and how is it different from back-end web development?
  • How do you know which HTML tag best suits which content?

Tips for HTML interview questions

Know the interview’s structure beforehand. There is no one structure for the front-end interview. So, before your interview, make sure to ask your recruiter about the format. Sometimes, your interview may use a whiteboard while others may use an online text editors. Make sure to know that environment that you will be using so that you are adjusted beforehand.

Prepare to talk about your projects. One of the first questions you will be asked in a frontend interview is around your past projects. It’s a good idea. to prepare a short speech about your projects including the tools used. This can include open source projects you’ve contributed to.

Approach coding questions with a system. For the technical questions of the interview, be sure to clarify that you understand the question. It’s a good idea to ask how you’ll be evaluated before you jump in, as it may change your strategy. Prioritize a mutual understanding with your interviewer so you can and adapt to feedback.

Approach the problem from multiple angles. An interviewee that gets stuck on one approach won’t make it too far. Don’t get set on one approach. A recruiter wants to know that you can take feedback. and adapt as needed. So, try to approach the problem from multiple angles and articulate any alternatives.


The top 30+ HTML interview questions and answers

Now that we have a general sense of what a frontend interview entails, let’s dive into HTML. We know that HTML is just one part of the picture, but it is the foundation of web development; having a strong grasp on this is the only way to progress with web development. Let’s take a deep dive into 30+ HTML related questions you can expect to see in a coding interview.


General

1. What is HTML?

HTML, which stands for Hyper Text Markup Language, is a standard text formatting language used to create pages on the web. The language allows text to be more interactive and dynamic. Beyond that, it can turn text into images, tables, links, and more.


2. What are W3C and WHATWG?

The World Wide Web Consortium (W3C) is a community of developers that works towards setting a set of global standards for development.

WHATWG (Web Hypertext Application Technology Working Group, was created during a W3C workshop led by Apple, Mozilla, and Opera in 2004. WHATWG is a community of developers that focuses on specifically setting HTML standards to fulfill the needs of users.


3. What is the basic structure of the HTML template?

<html>
      <head>
                <title></title>
      </head>
      <body>
      </body>
</html>

4. What are attributes?

Each tag can take in additional attributes that change the way the tag behaves. For example, an input tag has a type attribute, which allows you to specify whether the input field is a text field, checkbox, or radio button among other options.


5. How do you use attributes?

Attributes are specified within the HTML tag, inside the two brackets. An attribute field is followed by an equals sign and the value of the attribute is closed by double quotes . Make sure not to include any spaces before and after the equals sign for good practice. You can use multiple attributes one after another, separated by a space.

Here’s an example:

<input type="text" />

<input type="checkbox" />

<input type="radio" value="on" />

6. What are entities in HTML?

HTML character entities are used to replace reserved characters in HTML. You can also replace characters that are not present on your keyboard by using entities.


7. How can you reduce a page’s load time?

A basic rule to optimize our page’s loading time is to reduce the download size of our elements on the web page, as well as reduce the number of HTTP requests.

We can also follow some of the techniques below:

  • File compression
  • File concatenation
  • Re-organizing and refining code
  • Using internal and external style sheets and minimizing inline CSS
  • Using a CDN for media files
  • Hosting our website’s assets on different domains while also reducing DNS lookups

HTML5

8. What is HTML5?

HTML5 is the most recent version of the Hypertext Markup Language. HTML5 introduces several new features:

  • Adding new attributes
  • Allow offline editing
  • Adding new parsing rules to enhance flexibility
  • Support (Web SQL)
  • Support Protocol and MIME handler registration, allowing you to change the way of user interaction with documents.

9. What are the advantages of using HTML5?

HTML5 makes it significantly easier to build interactive websites when embedding video, audio, and graphics on your webpage. HTML5 supports multimedia technology and graphical content to the web without having to use third-party plugins like Flash.

More features:

  • Geolocation
  • Offline application cache
  • Error handling
  • Browser support and compatibility
  • Client-side database

Supports new API:

  • Browser History management
  • Drag and Drop
  • 3D drawing on webpage
  • Time media playback

Supported applications include:

  • Web workers - JavaScript
  • Local file access
  • Application cache
  • Local data storage
  • Local SQL database

10. What are semantic elements in HTML5?

Semantic HTML provides meaning to a webpage rather than just the presentation aspect of a webpage. For example, a p tag indicates that the text is a paragraph. This is both semantic and presentation in nature as the browser knows how to display a paragraph, and people know what paragraphs are.

In contrast, tags like <b> and <i> are not semantic because they only tell the browser what the text should look like in terms of presentation. They do not provide additional meaning to the markup semantically.


11. What is an API for HTML5?

An API, which stands for Application Programming Interfaces, is a way to build various web applications through pre-built components. Developers can more quickly build their applications by using components from existing APIs into their new site.


12. Some APIs in HTML5 are:

  • Data transfer API
  • Media API
  • User Interaction
  • History
  • Command API
  • Text Track API
  • HTML Geolocation
  • HTML Local Storage
  • Constraint Validation API

13. What is the purpose of <!Doctype html>?

Doctype is declared at the top of every HTML5 page, instructing the web browser on the version and type of HTML being used in the document. This is important because it allows the browser to read and load the document properly.

There are three types of Doctypes:

  • Strict Doctype
  • Frameset Doctype
  • Transitional Doctype

Succeed in your frontend interview.

Avoid waiting another 6 months to apply by taking our HTML coding interview course. Educative’s text-based courses are easy to skim and feature live coding environments, making learning quick and efficient.

HTML for Front-end Interviews


Tags

14. What are tags?

HTML tags are composed of an opening tag, content, and an ending tag. HTML tags are utilized to create HTML documents and render specific properties for a text element. Each HTML tag has a different set of properties.

Syntax: <tag> content </tag>


15. What is the anchor tag?

In HTML, the anchor tag is used to link between two different sections of a page or two different web pages altogether. The form for the anchor tag is as seen below:

<a href="link">Visit link</a>

16. Which HTML tag is used to display data in a tabular form?

To display data in a tabular form, we can use the HTML table tag. Here is the list of tags involved when creating a table:

  • <table>: defines a table
  • <tr>: defines a table row
  • <th>: defines a header cell
  • <td>: defines a cell
  • <caption>: defines a table caption
  • <colgroup>: specifies a group of one or more columns in a table for formatting
  • <col>: used with <colgroup> to specific properties for each column
  • <tbody>: groups the body content in a table
  • <thead>: groups the header content in a table
  • <tfooter>: groups the footer content in a table

17. What is an iFrame?

The <iframe> tag is used to display a webpage within a web page. By using the <iframe> tag, we can insert outside documents into the main HTML document easily. A common example of the <iframe> tag is banner ads on websites from a third party platform. Using iframes can introduce security risks because the website is now vulnerable to cross-site attacks.


18. What are the media element tags introduced by HTML5?

Here’s a list of new element tags introduced by HTML5:

  • <audio>: Used for multimedia sounds, audio streams, music, embed audio content without having to utilize an additional plugin like the flash player
  • <source>: Used for multiple media resources in media elements, including audio, video, picture, and more
  • <embed>: Used for external applications or embedded content like a plug-in
  • <video>: Used for video content like video streams, movie clips, and more
  • <track>: Used for adding subtitles containing text in video or audio elements.

19. What are the common lists used when designing a webpage?

There are several different types of lists used when designing a webpage. Here are the most common ones:

  • Ordered list: List is displayed in a number format from 1 to n. Ordered list can be created using the ol tag.

  • Unordered list: List is displayed using bullet points. Unordered list can be created using the ul tag.

  • Definition list: List is displayed in definition form like a dictionary. The dl, dt, and dd tags are used to create a definition list.


20. What is the canvas element in HTML5?

The <canvas> element is a container to draw graphics on web pages using a scripting language like Python or JavaScript. The element allows for scriptable and dynamic rendering of 2D shapes and images. In canvas, there are several different approaches to drawing paths, boxes, circles, text, and more.


Other / Miscellaneous

21. What is a stylesheet?

A stylesheet is created to build a consistent and concise style template that can be applied to your web pages. A stylesheet provides extra elements in terms of the design, look, and formatting of your document. Typically, we use CSS to specify the template in your stylesheet.


22. How many types of headings can an HTML document support?

An HTML document can support six level of heading from <h1> to <h6>.

<h1> an h1 </h1>
<h2> an h2 </h2>
<h3> an h3 </h3>
<h4> an h4 </h4>
<h5> an h5 </h5>
<h6> an h6 </h6>

23. Using an anchor tag, how can you open a URL into a new tab when clicked?

To direct a user to an URL into a new tab upon being clicked, we can set the target attribute equal to _blank. See the example below:

<a href="https://www.educative.io" target="_blank">Visit Educative!</a>

24. What is an SVG?

SVG, which stands for Scalable Vector Graphics, is an XML based format to draw vector images. SVG images are defined with XML text files, which we can create and edit with a text editor. We can use SVG to create vector-like diagrams: pie charts, 2-dimension graphs, etc.

<svg width="100" height="100">    
 <circle cx="50" cy="50" r="40" stroke="yellow" stroke-width="4" fill="red" />    
</svg>   

More practice questions

Congratulations on reviewing these problems! The questions above should give you a strong sense of what lies ahead in an interview. These are the most common questions, but there is still a lot more to learn!

To get you up to speed, we’ve compiled a list of more HTML questions you might expect to see in a front-end interview. Be sure to prepare as many as you can and recognize the patterns that will speed up your process.

All of these questions and more are answered in Educative’s definitive HTML study guide for coding interviews.

  1. Do all HTML tags have an end tag?

  2. What is formatting in HTML?

  3. What is the difference between HTML elements and tags?

  4. What is an image map?

  5. How to create a nested webpage in HTML?

  6. What is the difference between DIV and SPAN in HTML?

  7. How to make a picture of a background image of a web page?

  8. What are empty elements?

  9. What is the use of a span tag? Give one example.

  10. Why is a URL encoded in HTML?

  11. Which type of video formats are supported by HTML5?

  12. What is the use of figcaption tag in HTML 5?

  13. What is the purpose of using alternative texts in images?

  1. How to create a new HTML element?

  2. Can you create a multi-colored text on a web page?

  3. How to make a picture of a background image of a web page?

  4. What is the advantage of collapsing white space?

  5. When is it appropriate to use frames?

  6. What is the hierarchy that is being followed when it comes to style sheets?

  7. How do you create text on a webpage that allows you to send an email when clicked?

  8. How are active links different from normal links?

  9. What are the different tags to separate sections of text?

  10. How can we comment in HTML?

  11. What are inline elements and block-level elements in HTML?


Wrapping up and resources

Having a good foundation of your HTML understanding is vital if you want to pass the frontend coding interview and not get stuck on the basics. Once you feel up to speed on HTML, you’ll want to move onto to CSS, JavaScript, and advanced web dev concepts that unite them all.

If you are looking for a one-stop-shop for your frontend interview prep, check out our frontend interview prep course, HTML for Front-end Interviews. It walks you through all the need-to-know concepts with hands-on practice, real-world examples, and more.


Keep reading about HTML and coding interviews


WRITTEN BYAaron Xie

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