Top 15 HTML Interview Questions and Answers

Boost your interview prep with these Top 15 HTML Interview Questions and Answers, covering essential topics for beginners and experienced developers.

Q1. What is HTML?

Answer:
HTML (HyperText Markup Language) is the standard markup language used to create web pages. It defines the structure of a webpage using elements like <p>, <h1>, <div>, etc.

Q2. What are tags and attributes in HTML?

Answer:

Tags: HTML elements enclosed in angle brackets (< >). Example: <p>, <h1>, <img>.
Attributes: Provide additional information about elements. Used to define the properties of tags. Example: src for image tag, height ,width for paragraph tag.

<img src=”img.jpg” />

<p style=”height:200px;width:300px;”>This is paragraph 1</p>

Q3. What is HTML5? How is it different from HTML4?

Answer:
HTML5 is the latest version of HyperText Markup Language, designed to improve the structure, flexibility, and functionality of web pages. It introduces new elements, and attributes making it easier to develop modern web applications.
Key differences from HTML4:

New semantic elements: <header>, <footer>, <article>, <section>, etc.
New form input types: email, date, number, range, etc.
Support for multimedia with <audio> and <video> tags.
Improved storage: Web Storage (localStorage, sessionStorage) replaces cookies.
Better support for mobile and responsive design.

Q4. What are HTML forms and how are they used?

Answer:
Forms collect user input using <input>, <textarea>, <select>, and <button>.

Name: <input type=”text” name=”name”><br>

Email: <input type=”email” name=”email”><br>

<button type=”submit”>Submit</button>

</form>

action: URL where data is sent.

method: HTTP method (GET or POST).

Q5. How does HTML5 handle multimedia content?

Answer:
HTML5 introduces the <audio> and <video> tags to embed multimedia content without third-party plugins like Flash.
Example:

Your browser does not support the video tag.

</video>

Features:

Native playback support for different formats.
controls attribute provides play, pause, and volume options.
Multiple <source> elements can be used to support different formats.

Note: Do read Top HTML Interview Questions for Freshers

Q6. What is the difference between localStorage and sessionStorage?

Answer:
Both are part of the Web Storage API used for storing key-value pairs in the browser.

localStorage: Data persists even after the browser is closed.
sessionStorage: Data is stored temporarily and removed when the session ends (the browser is closed).
Example:

Q7. What are the new input types introduced in HTML5?

Answer:
HTML5 introduces several new <input> types to enhance form validation and user experience:

email – Validates email format.
date – Provides a date picker.
number – Allows numeric input.
range – Creates a slider.
tel – For telephone number input.
color – Provides a color picker.

Q8. What is the difference between <b> and <strong>, and between <i> and <em>?

Answer:

<b> (bold) vs. <strong> (strong importance):
- <b> applies only visual styling (bold).
- <strong> conveys meaning and is important for SEO and screen readers.
<i> (italic) vs. <em> (emphasis):
- <i> is for styling purposes (italic text).
- <em> gives emphasis, making it more meaningful in screen readers.

Q9. What is the difference between cookies, localStorage, and sessionStorage?

Q10. How does HTML5 improve form validation?

Answer:
HTML5 introduces built-in form validation without JavaScript using:

Required fields: required attribute.
Pattern validation: pattern attribute with regex.
Number range: min and max attributes.
Email and URL validation: type=”email” and type=”url”.

Example:

Q11. What is the difference between block, inline, and inline-block elements?

Answer:

Block elements: Take up the full width (e.g., <div>, <p>, <h1>).
Inline elements: Take up only as much width as needed (e.g., <span>, <a>, <strong>).
Inline-block elements: Behave like inline elements but allow width and height (e.g., <button>, <input>).

Q12. What is the difference between <div> and <span>?

Answer:

<div> is a block-level element that takes the full width and is used to group content.
<span> is an inline element used to apply styles to a part of text or an inline block.

Q13. How does HTML5 improve SEO?

Answer:

Semantic elements (<article>, <nav>, <header>, <footer>) help search engines understand page structure.
Faster loading times with <async> and <defer> improve rankings.
Mobile-friendly elements enhance user experience.

Q14. What is the difference between the get and post methods used with form tag?

Answer:

The GET and POST methods are two HTTP request methods used with the <form> tag in HTML. Here’s the key difference between them:

GET Method

Data is sent in the URL as query parameters (e.g., ?name=John&age=30).
Visible in the browser’s address bar, making it less secure.
Limited to 2048 characters (varies by browser).
Suitable for retrieving data (e.g., search forms).
Can be bookmarked and cached.

POST Method

Data is sent in the request body, not visible in the URL.
More secure (suitable for sensitive data like passwords).
No size limit for data.
Used for submitting or modifying data (e.g., login, registration).
Cannot be bookmarked or cached.

When to use what?

Use GET when retrieving data (e.g., search queries, filters).
Use POST when sending sensitive or large data (e.g., login, file upload).

Q15. What are semantic tags and non-sematic tags in html5?

Answer:

1. Semantic Tags

Definition:
Semantic tags in HTML5 clearly describe their meaning both to the browser and developers. These tags improve readability, SEO, and accessibility.

Example:

<header>- defines a page or section header

<nav>- represents the navigation links

<section>- Groups the related content together

<article> – Represents an independent article

2. Non-Semantic Tags

Definition:
Non-semantic tags do not clearly define their content. They are generic containers used for styling and layout purposes.

Example:

<div> – A generic block-level container

<span>A generic inline container

When to Use Which?

Use Semantic Tags whenever possible to make the structure clear and SEO-friendly.
Use Non-Semantic Tags (div and span) only when no appropriate semantic tag is available (e.g., for styling or layout purposes).

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