Top HTML Interview Questions for Frontend Developers

Hey there, frontend enthusiasts! ? Whether you're gearing up for your first interview or brushing up for your next big opportunity, mastering HTML is a must. Here's a curated list of the most common HTML interview questions with practical examples. Let's dive in! ?

---

1. What are semantic HTML tags?

Semantic tags clearly describe their purpose in a web page. They make your code more readable and improve SEO. ?

Example:

<!-- Semantic -->
<header>
  <h1>Welcome to My Blog</h1>
</header>
<article>
  <h2>How to Code</h2>
  <p>Start by learning the basics...</p>
</article>

<!-- Non-semantic -->
<div>



<p><strong>Why it matters:</strong> Semantic tags improve accessibility and help search engines understand your content better.</p>


<hr>

<h3>
  
  
  2. <strong>What is the difference between id and class attributes?</strong>
</h3>

<ul>
<li>
id: Unique identifier, used once per page.</li>
<li>
class: Can be reused multiple times for styling or grouping elements.</li>
</ul>

<p><strong>Example:</strong><br>
</p>

<pre class="brush:php;toolbar:false"><!-- Using id -->
<div>



<p><strong>Pro Tip:</strong> Use id for unique elements like headers or footers, and class for reusable components.</p>


<hr>

<h3>
  
  
  3. <strong>What are void elements in HTML?</strong>
</h3>

<p>Void elements are self-closing and don’t have a closing tag.</p>

<p><strong>Examples:</strong><br>
</p>

<pre class="brush:php;toolbar:false"><img src="image.jpg" alt="A beautiful view">
<input type="text" placeholder="Enter your name">
<hr>

Fun Fact: Adding a closing tag to void elements is invalid HTML!

---

4. How do you include JavaScript in an HTML document?

There are three ways to include JavaScript:

1) Inline:

   <button onclick="alert('Hello!')">Click Me</button>

2) Internal:

   <script>
     console.log('Hello from internal script!');
   </script>

3) External:

   <script src="script.js"></script>

Pro Tip: External scripts are preferred for better separation of concerns. ?️

---

5. What is the purpose of the alt attribute in images?

The alt attribute provides alternative text for an image when it’s not displayed or for screen readers.

Example:

<img src="logo.png" alt="Company Logo">

Why it’s important: Enhances accessibility and improves SEO ranking.

---

6. What are the differences between inline, block, and inline-block elements in HTML?

• Inline: Doesn’t start on a new line and only takes up as much width as necessary.
• Block: Starts on a new line and takes up the full width available.
• Inline-block: Behaves like an inline element but allows setting width and height.

Example:

<!-- Inline -->
<span>This is inline</span>
<span>Another inline</span>

<!-- Block -->
<div>This is block</div>
<div>Another block</div>

<!-- Inline-block -->
<div>



<p><strong>Pro Tip:</strong> Use inline-block for layouts where you need elements side-by-side with specific dimensions.</p>


<hr>

<h3>
  
  
  7. <strong>What are data attributes in HTML?</strong>
</h3>

<p>Custom attributes to store extra data without cluttering your DOM.</p>

<p><strong>Example:</strong><br>
</p>

<pre class="brush:php;toolbar:false"><button data-user-id="123" onclick="handleClick(this)">Click Me</button>
<script>
  function handleClick(button) {
    alert(`User ID: ${button.dataset.userId}`);
  }
</script>

Why they’re handy: Great for passing data to JavaScript without hardcoding.

---

8. How can you make an HTML element accessible?

• Use proper semantic tags.
• Add aria-* attributes for better screen reader support.

Example:

<button aria-label="Submit Form">Submit</button>

Pro Tip: Test your website with screen readers for real-world accessibility. ?

---

9. What’s the difference between and tags?

• : Defines a relationship between the document and an external resource (like CSS).
• : Creates a hyperlink.

Example:

<!-- Semantic -->
<header>
  <h1>Welcome to My Blog</h1>
</header>
<article>
  <h2>How to Code</h2>
  <p>Start by learning the basics...</p>
</article>

<!-- Non-semantic -->
<div>



<p><strong>Why it matters:</strong> Semantic tags improve accessibility and help search engines understand your content better.</p>


<hr>

<h3>
  
  
  2. <strong>What is the difference between id and class attributes?</strong>
</h3>

<ul>
<li>
id: Unique identifier, used once per page.</li>
<li>
class: Can be reused multiple times for styling or grouping elements.</li>
</ul>

<p><strong>Example:</strong><br>
</p>

<pre class="brush:php;toolbar:false"><!-- Using id -->
<div>



<p><strong>Pro Tip:</strong> Use id for unique elements like headers or footers, and class for reusable components.</p>


<hr>

<h3>
  
  
  3. <strong>What are void elements in HTML?</strong>
</h3>

<p>Void elements are self-closing and don’t have a closing tag.</p>

<p><strong>Examples:</strong><br>
</p>

<pre class="brush:php;toolbar:false"><img src="image.jpg" alt="A beautiful view">
<input type="text" placeholder="Enter your name">
<hr>

Quick Tip: Don’t confuse the two—one is for resources, the other for navigation!

---

10. What is the doctype declaration?

The declaration defines the HTML version used in the document.

Example:

   <button onclick="alert('Hello!')">Click Me</button>

Fun Fact: Modern browsers default to HTML5 even if the doctype is missing, but it’s best to include it.

---

Quiz Time! ?

Let’s test your knowledge. Answer these in the comments below! ?

1. What tag would you use for defining a navigation menu?

• a)
• b)
• c)

1. Which attribute uniquely identifies an element in the DOM?

• a) class
• b) id
• c) style

1. True or False: The tag is a semantic HTML tag.

Drop your answers below and let’s discuss! ?

The above is the detailed content of Top HTML Interview Questions for Frontend Developers. For more information, please follow other related articles on the PHP Chinese website!