40 Must-Know HTML Interview Questions & Answers in 2025
Updated on Feb 10, 2025 | 22 min read | 248.7k views
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Updated on Feb 10, 2025 | 22 min read | 248.7k views
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Hypertext Markup Language (HTML) is used to structure content on web browsers. HTML elements help create sections, paragraphs, and links. While HTML isn't a programming language and doesn’t provide dynamic functionality, it’s an important tool for web development, internet navigation, and web documentation.
For both applicants and interviewers, it is important to review typical questions covering HTML concepts and use cases to gain a solid understanding.
To aid in this, we have compiled a straightforward list of HTML interview questions, organized into basic, intermediate, and advanced levels. Interviewers can use it to assess candidates, while developers can refer to it to prepare for their HTML developer interviews.
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HTML or HyperText Markup Language is the standard language for creating and structuring web pages.
It is used to structure content on the web by defining elements such as headings, paragraphs, links, and images. HTML stands for HyperText Markup Language.
We have further categorized HTML interview questions into basic HTML interview questions, intermediate HTML interview questions, and advanced HTML interview questions.
Let’s dive in!
These questions are designed to assess a candidate's foundational knowledge of HTML. They cover the basics of HTML structure, common tags, and how they’re used in web development. These are ideal for those just starting out or applying for entry-level roles in web development.
1. Explain the structure of an HTML document.
The basic structure of an HTML document includes <!DOCTYPE html>, <html>, <head>, and <body>. The <head> contains meta information, and <body> contains the content. An HTML document begins with <!DOCTYPE html>, followed by <html>. Inside <html>, the <head> contains metadata, and <body> holds the visible content
2. How do you create a hyperlink in HTML?
To create a hyperlink, use the <a> tag with the href attribute to specify the destination URL.
<a href="https://www.example.com">Visit Example</a> creates a clickable link that directs users to the specified website.
3. What are heading tags in HTML?
HTML uses six heading tags (<h1> to <h6>) to define headings on a webpage. <h1> is the most important, and <h6> is the least important. <h1> is used for main headings, and <h2> through <h6> are used for subheadings, with each level decreasing in importance
4. How do you create ordered and unordered lists in HTML?
Use <ol> for ordered lists (numbered) and <ul> for unordered lists (bulleted). Each list item is enclosed in <li> tags. <h1> is used for main headings, and <h2> through <h6> are used for subheadings, with each level decreasing in importance.
5. How do you add an image to an HTML page?
The <img> tag is used to embed an image in HTML. The src attribute specifies the image source, and alt provides alternative text. <img src='image.jpg' alt='Description of image'> embeds an image and provides alternative text for accessibility.
6. How do you create a paragraph in HTML?
Use the <p> tag to create a paragraph in HTML. <p>This is a paragraph of text.</p> adds a block of text, separated by a blank line above and below.
7. What is the difference between inline and block-level elements?
Block elements take up the full width and start on a new line, while inline elements only take up the space needed and do not start on a new line. <div> is a block-level element, taking up the full width of the page. <span> is an inline element that only takes up the space required by its content.
8. Why is the <alt> attribute important in the <img> tag?
The alt attribute provides alternative text for images, useful for screen readers and in cases where the image cannot be displayed. It improves accessibility and ensures users can understand what an image represents, even if it doesn’t load.
9. What are the <br> and <hr> tags used for?
<br> is used to insert a line break, and <hr> is used to create a horizontal rule or divider. <br> adds a single line break, while <hr> inserts a horizontal line to visually separate sections of content
10. How do you link an external CSS file to an HTML document?
CSS files are linked using the <link> tag within the <head> section, with the href attribute pointing to the CSS file. <link rel='stylesheet' href='styles.css'> links an external CSS file to the HTML document, allowing the document to use external styles.
These questions focus on more advanced HTML concepts, such as HTML5 elements, forms, and how HTML interacts with CSS and JavaScript. They help assess a deeper understanding of web development techniques.
These questions are suitable for developers with some hands-on experience in web development. If you’ve moved beyond the basics and have practical experience, this section is for you.
11. What is the difference between HTML and HTML5?
In contrast to HTML, which offers basic structure and limited multimedia support, HTML5 introduces advanced features such as new semantic elements, native audio and video support, improved form controls, client-side storage, enhanced graphics capabilities, and better mobile optimization, making it more suitable for modern web development.
Take a look at this table highlighting the difference between HTML and HTML5:
Factor | HTML | HTML5 |
New Elements | Limited structural elements like <div>, <span>. | Introduced new semantic elements like <header>, <footer>, <article>, <section>, and <nav>. |
Multimedia Support | Relied on plugins like Flash for audio and video. | Native support for audio (<audio>) and video (<video>) elements, eliminating the need for external plugins. |
Graphics | No native support for 2D graphics. | Introduced <canvas> for drawing 2D graphics, enhancing interactive content. |
Form Controls | Basic form inputs, limited validation options. | Introduced new input types (e.g., email, date, range) and built-in validation for better form handling. |
Storage | No native client-side storage. | Introduced localStorage and sessionStorage for client-side data storage, enabling offline web apps. |
Mobile Optimization | No specific features for mobile devices. | HTML5 is designed with mobile optimization in mind, supporting touch events and responsive design. |
12. What is the difference between <article> and <section> in HTML5?
Both <article> and <section> are semantic HTML5 elements, but <article> is used for independent, self-contained content, while <section> groups related content. <article> represents an independent piece of content, like a blog post. <section> is used to group related content, like chapters in a book.
13. How do you create a form in HTML? What are the different input types?
Forms in HTML are created using the <form> tag, with input fields like <input type="text">, <input type="password">, <textarea>, and <select>. "<form> is used to create forms. You can use various input types like text, password, email, and number depending on the type of data being collected.
14. What is lazy loading and how do you implement it in HTML?
Lazy loading defers loading of non-critical resources like images until they're needed, improving performance. "Implement lazy loading by adding the loading='lazy' attribute to images and iframes. This defers loading until the content is within the viewport.
15. How do you create a table in HTML?
Tables in HTML are created using the <table>, <tr>, <td>, and <th> tags. <thead>, <tbody>, and <tfoot> help structure the table's content. <table><tr><th>Header</th></tr><tr><td>Data</td></tr></table> creates a table with headers and data rows. thread and tbody provide structure.
16. What is the purpose of the <meta> tag in HTML?
The <meta> tag provides metadata about the HTML document, such as character set, page description, keywords, and viewport settings. <meta charset='UTF-8'> defines the character encoding for the document. <meta name='description' content='Webpage description'> adds a description for SEO.
17. How do you ensure a website is accessible for screen readers?
To improve accessibility for screen readers, use proper semantic tags, provide aria attributes, and add alt text for images. Semantic tags like <nav>, aria-labels, and proper use of the alt attribute ensure a website is more accessible for users with disabilities.
18. What’s the difference between <div> and <span> elements?
<div> is a block-level element used for larger content sections, while <span> is an inline element for styling specific parts of text. <div> is used for grouping large blocks of content. <span> is used to style or manipulate smaller parts of text without disrupting the flow.
19. What is the purpose of the <nav> tag in HTML5?
The <nav> tag defines a section of the page containing navigation links, improving both SEO and accessibility. <nav> groups the primary navigation links of a website, such as menus or table of contents, making it easier for search engines and screen readers to understand.
20. Why are semantic tags like <header>, <footer>, and <article> important?
Semantic tags help define the meaning of the content for search engines and assistive technologies, improving both SEO and accessibility. Semantic tags make the content more understandable. For example, <header> marks the beginning of the page, while <footer> marks the end.
21. How do you embed a video or audio file in an HTML page?
Use the <video> and <audio> tags to embed multimedia, with support for multiple file formats via <source> tags.
<video controls><source src='video.mp4' type='video/mp4'></video> embeds a video file, and <audio> works similarly for audio files.
22. How do you ensure cross-browser compatibility with HTML code?
Testing in multiple browsers, using normalized stylesheets (like Normalize.css), and following HTML standards helps ensure compatibility. "Test in different browsers and use tools like Normalize.css to handle inconsistencies in rendering HTML elements across browsers.
23. What are ARIA roles, and how do they improve accessibility in HTML?
ARIA (Accessible Rich Internet Applications) roles are special attributes that can be added to HTML elements to enhance web accessibility for people with disabilities, especially those using screen readers or other assistive technologies.
ARIA roles help define elements for screen readers. Add role, aria-label, and aria-described by attributes to make the page accessible. "Use role='navigation', aria-label for better descriptions, and aria-described to improve accessibility for users relying on screen readers."
Here's how ARIA roles improve accessibility:
24. How do you implement responsive web design in HTML?
Responsive Web Design (RWD) ensures that a web page adapts to different screen sizes and device types (like desktops, tablets, and smartphones). It typically involves a combination of flexible layouts, media queries, and responsive images.
These are the ways to implement responsive design:
25. How can you create a multi-page, nested website structure using HTML?
To create a multi-page, nested website structure, you organize your content into several HTML files and use navigation links to connect them. A nested structure typically means having different sections or categories inside your website that users can explore.
Here's how you can set it up:
Step 1 - Create Multiple HTML Pages: For each page, you create a separate .html file (e.g., index.html, about.html, contact.html, etc.).
Step 2: Directory Structure: Organize your files into folders. For example:
/ (root directory)
├── index.html
├── about.html
├── contact.html
└── /assets
├── style.css
└── images
Step 3 - Links Between Pages: You can use <a> tags to link the different pages together in the navigation menu.
<nav>
<ul>
<li><a href="index.html">Home</a></li>
<li><a href="about.html">About</a></li>
<li><a href="contact.html">Contact</a></li>
</ul>
</nav>
Step 4- Nested Content: Inside each HTML file, you can nest elements inside <div>, <section>, <article>, etc., to organize the content in a structured manner.
<div class="main-content">
<section>
<h1>About Us</h1>
<p>Information about the company.</p>
</section>
</div>
Step 5 - Styling and Layout: Use CSS to style the navigation menu, headers, and content areas. Ensure that the layout works well across the different pages.
In this section on advanced-level HTML interview questions, we shall delve into more complex topics in HTML, such as performance optimization, advanced HTML5 features, and SEO integration. The focus is on writing efficient, clean, and scalable code.
These questions are designed for senior developers or advanced web designers who are experienced in web development and want to demonstrate expertise in advanced HTML concepts and best practices.
26. How do you optimize images in HTML for faster load times?
Image optimization is crucial for performance. Techniques include resizing images, using correct formats like WebP, and adding srcset. "To optimize images, use the correct size, format (like WebP), and srcset to provide responsive images for different screen sizes."
27. Explain the purpose of the <canvas> and <audio> elements in HTML5.
<canvas> allows for dynamic, scriptable rendering of 2D graphics, while <audio> embeds sound content. "<canvas> is used for drawing graphics via JavaScript. <audio> is used for embedding audio files directly into a webpage with playback controls."
28. How does the <title> tag impact SEO? What HTML tags are crucial for SEO optimization?
The <title> tag defines the page title, which is crucial for SEO. Other tags like <meta>, <h1>, and <alt> also play a role. "The <title> tag appears in search results and is key for SEO. Use tags like <h1> for headings and alt for image descriptions to improve SEO."
29. What are some best practices for writing clean HTML code?
Use semantic HTML, indent properly, keep your code DRY (Don't Repeat Yourself), and minimize unnecessary elements to maintain clean code. "Write semantic HTML, use proper indentation, avoid inline styles, and ensure the code is well-structured for readability and maintainability."
30. How would you improve a web page’s load time using HTML optimizations?
Reducing image sizes, lazy loading, deferring JavaScript, and minimizing HTML/CSS/JS files all help reduce page load time. "I would optimize images, use lazy loading, defer JavaScript, and minify HTML, CSS, and JavaScript files to improve load times."
31. How do you optimize <script> loading to improve page performance?
Defer or asynchronously load scripts to avoid blocking the rendering of the page, which can reduce load times. "Use the defer or async attribute on <script> tags to ensure scripts load without blocking the rendering of the page content."
32. How can you use data- attributes to store custom data in HTML elements?
The data-* attributes allow developers to store custom information in HTML elements for later use with JavaScript. "data-* attributes can be used to store custom data in elements. For example, <div data-id='123'> allows JavaScript to access this custom data easily.
33. What is the function of the meter element in HTML5?
The <meter> element in HTML5 is used to represent a scalar measurement within a known range, such as a progress bar or a rating system. It is typically used to display a value that is part of a predefined range, like disk usage, a score, or a temperature.
In the following example, the <meter> element shows the battery level as 60% of its total capacity, with the range defined from 0 to 1:
<label for="battery">Battery Level:</label>
<meter id="battery" value="0.6" min="0" max="1"></meter>
34. What is the Shadow DOM in HTML?
The Shadow DOM is a web standard that allows for the encapsulation of HTML, CSS, and JavaScript within a web component. It enables developers to create self-contained, reusable components with isolated styles and behaviors that do not interfere with the global document. The Shadow DOM is a key part of Web Components and allows components to maintain their own internal DOM structure while remaining separate from the main document's DOM.
The key components of Shadow DOM are:
This is how it works:
Here’s how you can create a Shadow DOM in HTML:
<!-- Host Element -->
<div id="host"></div>
<script>
// Attach Shadow DOM to host element
const shadowRoot = document.getElementById('host').attachShadow({mode: 'open'});
// Add content to the shadow DOM
shadowRoot.innerHTML = `
<style>
p { color: red; }
</style>
<p>This is inside the Shadow DOM</p>
`;
</script>
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35. How can you convert an inline element into a block-level element?
To convert an inline element into a block-level element, CSS is used to modify the display property of the element. By changing the display type, the behavior of the element can be adjusted to occupy the full width of its parent container.
Here’s how you can convert an inline element into a block-level element:
36. What is the difference between the <progress> and <meter> tags in HTML?
The <progress> and <meter> tags in HTML5 are both used to represent measurements, but they serve different purposes. The <progress> tag is used to represent the completion of a task, often with a value indicating the percentage of progress. It is typically used for tasks like file uploads or loading processes, where a value between 0 and 1 (or 0 to 100) reflects the progress.
On the other hand, the <meter> tag is used to represent a value within a known range, like a scale or gauge. It’s commonly used for things like disk usage or a rating system, where the value is within a specific range (e.g., 0 to 100), but it doesn't reflect the completion of a task. Essentially, while both tags represent measurements, <progress> is for task progress, and <meter> is for scalar data within a range.
37. How do WebSockets in HTML5 enable real-time communication in web applications,?
WebSockets in HTML5 provide a mechanism for establishing a persistent, full-duplex communication channel between a web browser (client) and a server. Unlike traditional HTTP requests, which are one-way and stateless, WebSockets allow both the client and the server to send and receive data at any time over a single connection.
WebSockets in HTML5 enable real-time, interactive communication by maintaining an open connection that allows messages to be sent back and forth between the client and server with minimal delay. This is especially useful for applications that require live updates and instant data exchange.
Here's how they work:
Below is an example of the use of WebSocket:
// Open WebSocket connection
const socket = new WebSocket('ws://example.com/socket');
// When the connection is open
socket.onopen = function(event) {
console.log('Connection established');
socket.send('Hello Server!');
};
// When a message is received from the server
socket.onmessage = function(event) {
console.log('Message from server: ', event.data);
};
// When the connection is closed
socket.onclose = function(event) {
console.log('Connection closed');
};
38. What is MathML in HTML5, and how is it used to display mathematical content?
MathML (Mathematical Markup Language) is an XML-based language used to represent mathematical notations and structures within web pages. In HTML5, MathML enables the inclusion of complex mathematical formulas, equations, and symbols directly in the HTML document. It allows for a semantically rich and accessible representation of mathematical content, which can be styled and manipulated using CSS and JavaScript.
Here is how MathML is used to display mathematical content:
39. What techniques can you use to make HTML forms accessible for users with disabilities?
Ensuring accessibility in HTML forms is crucial for providing an inclusive web experience for users with disabilities. Below are several techniques to enhance the accessibility of HTML forms:
1. Use Semantic HTML
2. ARIA Attributes
3. Keyboard Accessibility
4. Error Handling and Feedback
5. Provide Clear Instructions
6. Visual Clarity and Focus
40. How does the <canvas> element in HTML5 work, and how does it compare to the <svg> element in terms of rendering methods and ideal use cases?
The <canvas> element in HTML5 is used to draw graphics dynamically via JavaScript. It provides a drawable area in the form of a bitmap, where pixels can be manipulated directly. The <canvas> element is primarily used for rendering graphics, animations, and interactive visualizations. Here's a detailed breakdown of how it works and how it compares to the <svg> element.
How the <canvas> Element Works:
1. Basic Structure:
2. Rendering via JavaScript:
This is an example of a drawing on canvas:
var canvas = document.getElementById('myCanvas');
var ctx = canvas.getContext('2d');
ctx.fillStyle = 'red';
ctx.fillRect(10, 10, 100, 100); // Draw a red rectangle
3. Pixel-Based Rendering:
Following is a comparison between <canvas> and <svg> elements:
Factor |
<canvas> |
<svg> |
Rendering Model | Bitmap-based (pixel manipulation) | Vector-based (geometric shapes, paths) |
Use Case | Ideal for complex, dynamic graphics like games, animations, and image manipulation. | Ideal for scalable, static, or simple interactive graphics like icons, logos, and charts. |
Performance | Better for real-time rendering with lots of dynamic content (e.g., games, complex animations). | Can be less efficient with many elements, but works well for simple or static graphics. |
Scalability | Resolution-dependent (loses quality when zoomed or resized). | Scalable without losing quality (resizes cleanly at any resolution). |
Manipulability | Once drawn, content cannot be easily manipulated; you need to redraw it. | Each individual element (circle, rectangle, path, etc.) is part of the DOM and can be easily manipulated via JavaScript and CSS. |
Interactivity | Less suitable for individual element interactivity; works well for fast, frame-based updates. | Very suitable for interactivity, as each element can be targeted and manipulated individually (e.g., clickable elements, CSS animations). |
Preparing for an HTML interview requires a combination of technical knowledge and practical problem-solving skills. Here are some tips to help you get ready:
HTML is the foundation of web development, and mastering it opens up various career opportunities in the tech industry. Individuals skilled in HTML can pursue various roles, such as:
Let’s take a look at the salary prospects of these roles:
Job Role | Approximate Salary Range |
Front-End Developer | ₹3L - ₹9L/yr |
Web Designer | ₹3L - ₹9L/yr |
UI/UX Developer | ₹4L - ₹8L/yr |
Email Developer | ₹4L - ₹10.0L/yr |
Full-Stack Developer | ₹4L - ₹10.0L/yr |
Web Development Manager | ₹3L - ₹7L/yr |
Source: Glassdoor
Read More on: HTML Developer Salary
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Through this blog, we aim to cover the topmost HTML interview questions to help you prepare for your next web development role. From basic tags to advanced HTML5 features, having a solid understanding of these concepts will help you confidently tackle interview challenges.
However, mastering HTML is just the beginning. If you're looking to further level up your skills and take your career to the next stage, online courses can provide the comprehensive training you need.
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References:
https://www.naukri.com/code360/library/html-interview-questions
https://deepprogrammer.medium.com/part-3-advanced-html-interview-questions-with-answers-and-code-examples-9987e2718846
https://www.tutorialspoint.com/html/index.htm
https://www.interviewbit.com/html-interview-questions/#what-are-forms-and-how-to-create-them-in-html
https://www.turing.com/interview-questions/html
https://www.glassdoor.co.in/Salaries/front-end-developer-salary-SRCH_KO0,19.htm
https://www.glassdoor.co.in/Salaries/new-delhi-web-designer-salary-SRCH_IL.0,9_IM1083_KO10,22.htm
https://www.glassdoor.co.in/Salaries/ui-ux-developer-salary-SRCH_KO0,15.htm
https://www.glassdoor.co.in/Salaries/email-developer-salary-SRCH_KO0,15.htm
https://www.glassdoor.co.in/Salaries/full-stack-developer-salary-SRCH_KO0,20.htm
https://www.glassdoor.co.in/Salaries/web-development-manager-salary-SRCH_KO0,23.htm
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