Badge component in Bootsrap - Mini Project: Build & Apply

Bootstrap Badge Component

📖 Scenario: You are creating a simple webpage to show a notification badge next to a message. Badges are small count indicators often used in apps to show new messages or alerts.

🎯 Goal: Build a webpage that displays a message with a Bootstrap badge showing the number 5 as a notification count.

📋 What You'll Learn

Use Bootstrap 5 classes to create a badge

Display the badge next to the text 'Messages'

Use the badge color bg-primary

Include the correct HTML5 document structure with lang, charset, and viewport meta tags

Make sure the badge is accessible with appropriate semantic HTML

💡 Why This Matters

🌍 Real World

Badges are commonly used in websites and apps to show notifications, message counts, or status indicators.

💼 Career

Knowing how to use Bootstrap badges helps you quickly build user interfaces that communicate important information clearly and accessibly.

1

Create the basic HTML structure

Create a basic HTML5 document with lang="en", charset="UTF-8", and a viewport meta tag. Add a <main> element inside the <body>.

Bootsrap

    
    
    Badge Example


    
        
    

Hint

Remember to include the lang attribute in the <html> tag and the meta tags inside <head>.

2

Add Bootstrap CSS link

Inside the <head>, add the Bootstrap 5 CSS CDN link: https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/css/bootstrap.min.css using a <link> tag with rel="stylesheet".

Bootsrap

    
    
    Badge Example
    


    
    

Hint

Use a <link> tag with rel="stylesheet" and the exact href URL for Bootstrap CSS.

3

Add the message text with a badge

Inside the <main> element, add a <span> with the text Messages. Next to it, add a Bootstrap badge using a <span> with classes badge and bg-primary that displays the number 5.

Bootsrap

    
    
    Badge Example
    


    
        
    

Hint

Use two <span> elements: one for the text and one for the badge with classes badge and bg-primary.

4

Make the badge accessible and visually clear

Add an aria-label="5 new messages" attribute to the badge <span> to improve accessibility. Also, wrap the message and badge inside a <div> with class d-inline-flex align-items-center gap-2 to align them nicely.

Bootsrap

    
    
    Badge Example
    


    
        
    

Hint

Use a <div> with Bootstrap flex classes to align items and add aria-label to the badge for screen readers.

Practice

1. What is the main purpose of a Bootstrap badge component?

easy

A. To style form input fields

B. To create large banners for page headers

C. To add navigation menus

D. To highlight small pieces of information like counts or labels

Solution

1. Step 1: Understand the badge role

   Badges are used to show small bits of info such as counts or labels next to text or buttons.

2. Step 2: Compare options

   Options A, B, and C describe other Bootstrap components or uses, not badges.

3. Final Answer:

   To highlight small pieces of information like counts or labels -> Option D

4. Quick Check:

   Badge = small info highlight [OK]

Hint: Badges show small info like numbers or labels [OK]

Common Mistakes:

• Confusing badges with navigation or headers
• Thinking badges style large elements
• Using badges for form inputs

2. Which of the following is the correct syntax to create a Bootstrap badge with a primary color?

easy

A. New

B. New

C. New

D. New

Solution

1. Step 1: Check Bootstrap badge syntax

   Bootstrap badges use a span with class badge plus a background color class like bg-primary.

2. Step 2: Validate each option

   New uses correct tags and classes. Options A, B, and D use incorrect tags or class names.

3. Final Answer:

   <span class="badge bg-primary">New</span> -> Option C

4. Quick Check:

   Use span.badge.bg-primary [OK]

Hint: Use <span> with classes badge and bg-color [OK]

Common Mistakes:

• Using <div> instead of <span>
• Missing the 'badge' class
• Using wrong class names like badge-primary

3. What will be the visual result of this code?

<button type="button" class="btn btn-secondary">Messages <span class="badge bg-danger">5</span></button>

medium

A. A secondary button labeled 'Messages' with a red badge showing number 5

B. A red button labeled 'Messages' with a secondary badge showing number 5

C. A button labeled 'Messages' with no badge visible

D. A secondary button labeled 'Messages' with a blue badge showing number 5

Solution

1. Step 1: Analyze button and badge classes

   The button uses btn btn-secondary which styles it gray. The badge uses badge bg-danger which styles it red.

2. Step 2: Understand visual output

   The button text is 'Messages' and the badge with number 5 appears in red next to it.

3. Final Answer:

   A secondary button labeled 'Messages' with a red badge showing number 5 -> Option A

4. Quick Check:

   btn-secondary + badge bg-danger = gray button + red badge [OK]

Hint: bg-danger means red badge color [OK]

Common Mistakes:

• Confusing button and badge colors
• Expecting badge to be blue or missing
• Ignoring badge inside button

4. Identify the error in this badge code:

<span class="badge badge-primary">99</span>

medium

A. The span tag cannot be used for badges

B. The class 'badge-primary' is outdated; should use 'bg-primary' instead

C. The number 99 is too large for a badge

D. Missing closing tag for span

Solution

1. Step 1: Check Bootstrap badge color class

   In Bootstrap 5+, color classes for badges use bg-primary, not badge-primary.

2. Step 2: Validate other parts

   The span tag is correct, number size is fine, and the closing tag is present.

3. Final Answer:

   The class 'badge-primary' is outdated; should use 'bg-primary' instead -> Option B

4. Quick Check:

   Use bg-primary, not badge-primary [OK]

Hint: Use bg-primary for badge color, not badge-primary [OK]

Common Mistakes:

• Using old Bootstrap 4 class names
• Thinking span is invalid tag
• Assuming number size matters

5. You want to add a badge inside a navigation link that shows the number of unread notifications. Which is the best way to do this for accessibility and styling?

<a href="#" class="nav-link">Notifications <?></a>

What should replace <?>?

hard

A. <span class="badge bg-info" aria-label="unread notifications">3</span>

B. <div class="badge bg-info">3</div>

C. <span class="badge bg-info"><strong>3</strong></span>

D. <span class="badge bg-info" role="button">3</span>

Solution

1. Step 1: Choose correct tag and classes

   Badges should use span with badge and color class like bg-info.

2. Step 2: Add accessibility attribute

   Adding aria-label describes the badge meaning for screen readers, improving accessibility.

3. Final Answer:

   <span class="badge bg-info" aria-label="unread notifications">3</span> -> Option A

4. Quick Check:

   Use span.badge with aria-label for accessibility [OK]

Hint: Use aria-label on badge span for screen readers [OK]

Common Mistakes:

• Using div inside links (invalid HTML)
• Adding role=button unnecessarily
• Not adding aria-label for accessibility