Anchor tag basics in HTML - Performance & Optimization

Performance: Anchor tag basics

MEDIUM IMPACT

Anchor tags affect page load speed by triggering navigation and can impact interaction responsiveness when used improperly.

Creating clickable links for navigation

HTML

<a href="/target-page" aria-label="Go to target page">Click me</a>

Using a real href enables browser prefetching and faster navigation; no inline JS blocking rendering.

📈 Performance Gainnon-blocking navigation, faster interaction, better accessibility

Creating clickable links for navigation

HTML

<a href="#" onclick="doSomething(); return false;">Click me</a>

Using href="#" causes the browser to jump to the top and may trigger unnecessary reflows or reloads; inline JavaScript blocks rendering and delays interaction.

📉 Performance Costtriggers 1 reflow and blocks interaction until JS runs

Performance Comparison

Pattern	DOM Operations	Reflows	Paint Cost	Verdict
Anchor with href="#" and inline JS	Minimal DOM nodes	1 reflow on click	Low paint cost	[X] Bad
Anchor with valid href and no inline JS	Minimal DOM nodes	0 reflows on click	Low paint cost	[OK] Good

Rendering Pipeline

Anchor tags with valid hrefs allow the browser to prepare navigation early, improving the critical rendering path. Improper use can cause layout shifts or block interaction.

→Style Calculation

→Layout

→Paint

→Composite

⚠️ BottleneckLayout and Interaction Delay

Core Web Vital Affected

INP

Anchor tags affect page load speed by triggering navigation and can impact interaction responsiveness when used improperly.

Optimization Tips

1Always use valid href attributes in anchor tags for better navigation performance.

2Avoid using href="#" as it causes unnecessary page jumps and reflows.

3Do not block rendering with inline JavaScript on anchor tags.

Performance Quiz - 3 Questions

What is a performance downside of using <a href="#"> with inline JavaScript for navigation?

A It improves browser prefetching.

B It reduces the file size of the page.

C It can cause unnecessary page jumps and block interaction.

D It speeds up page load time.

DevTools: Performance

How to check: Record a session while clicking anchor links; look for layout shifts or long tasks blocking interaction.

What to look for: Check for minimal layout recalculations and fast interaction response times.

Practice

1. What does the <a> tag do in HTML?

easy

A. Creates a clickable link to another page or resource

B. Defines a paragraph of text

C. Inserts an image into the page

D. Adds a heading to the page

Solution

1. Step 1: Understand the purpose of the <a> tag

   The <a> tag is used to create links that users can click to go to other pages or resources.

2. Step 2: Compare with other tags

   Other tags like <p>, <img>, and <h1> serve different purposes such as paragraphs, images, and headings.

3. Final Answer:

   Creates a clickable link to another page or resource -> Option A

4. Quick Check:

   Anchor tag = clickable link [OK]

Hint: Anchor tag always creates clickable links [OK]

Common Mistakes:

• Confusing <a> with <p> or <img>
• Thinking <a> adds images or text formatting
• Ignoring the clickable nature of <a>

2. Which of the following is the correct syntax to create a link to "https://example.com" with the text "Visit Example"?

easy

A. Visit Example

B. Visit Example

C. Visit Example

D. https://example.com

Solution

1. Step 1: Identify the correct attribute for link destination

   The correct attribute to specify the link URL is href inside the <a> tag.

2. Step 2: Check the tag and attribute usage

   <a href="https://example.com">Visit Example</a> uses <a> with href and link text correctly. Other options use wrong attributes or tags.

3. Final Answer:

   <a href="https://example.com">Visit Example</a> -> Option A

4. Quick Check:

   Use <a href="URL">text</a> for links [OK]

Hint: Use href attribute inside <a> for links [OK]

Common Mistakes:

• Using url instead of href attribute
• Using <link> tag instead of <a>
• Omitting href attribute

3. What will the following HTML code display in the browser?

<a href="#section2">Go to Section 2</a>
<h2 id="section2">Section 2</h2>

medium

A. A link that opens a new tab to a page named 'section2'

B. An error message because href cannot start with #

C. A clickable link labeled 'Go to Section 2' that scrolls to the heading 'Section 2' on the same page

D. Plain text 'Go to Section 2' with no link

Solution

1. Step 1: Understand href with # and id attribute

   The href="#section2" links to an element with id="section2" on the same page, causing the page to scroll there.

2. Step 2: Check the displayed content

   The link text 'Go to Section 2' is clickable and scrolls to the heading labeled 'Section 2'.

3. Final Answer:

   A clickable link labeled 'Go to Section 2' that scrolls to the heading 'Section 2' on the same page -> Option C

4. Quick Check:

   href="#id" scrolls to element with that id [OK]

Hint: href="#id" links inside same page [OK]

Common Mistakes:

• Thinking # means new page or error
• Expecting new tab to open
• Ignoring id attribute connection

4. Find the error in this anchor tag code:

<a href="www.example.com">Example</a>

medium

A. href attribute should be written as link

B. Incorrect closing tag, should be <a />

C. Text 'Example' should be inside quotes

D. Missing protocol like https:// in href URL

Solution

1. Step 1: Check href URL format

   The href value 'www.example.com' lacks the protocol (http:// or https://), so the browser treats it as a relative link.

2. Step 2: Understand correct URL usage

   To link to an external site, the URL must include the protocol like 'https://www.example.com'.

3. Final Answer:

   Missing protocol like https:// in href URL -> Option D

4. Quick Check:

   External links need full URL with protocol [OK]

Hint: Always include https:// for external links [OK]

Common Mistakes:

• Omitting https:// causes relative link errors
• Using self-closing tag incorrectly
• Misnaming href attribute

5. You want to create an email link that opens the user's email program to send mail to "[e-mail]". Which anchor tag is correct?

hard

A. Send Email

B. Send Email

C. Send Email

D. Send Email

Solution

1. Step 1: Identify the correct protocol for email links

   Email links use the mailto: protocol in the href attribute to open the email client.

2. Step 2: Check each option's syntax

   <a href="mailto:[e-mail]">Send Email</a> uses mailto:[e-mail] correctly. <a href="email:[e-mail]">Send Email</a> uses wrong protocol 'email:', while others lack the protocol or use incorrect formats like 'mailto://'.

3. Final Answer:

   <a href="mailto:[e-mail]">Send Email</a> -> Option B

4. Quick Check:

   Email links use mailto: prefix [OK]

Hint: Use mailto: before email address in href [OK]

Common Mistakes:

• Using email: instead of mailto:
• Omitting mailto: prefix
• Adding extra slashes after mailto: