Horizontal collapse in Bootsrap - Mini Project: Build & Apply

Horizontal Collapse with Bootstrap

📖 Scenario: You are building a simple webpage where users can click a button to show or hide some content horizontally. This is useful for menus or side panels that slide open and closed.

🎯 Goal: Create a horizontal collapse section using Bootstrap. When the user clicks the button, the content area should expand or collapse horizontally.

📋 What You'll Learn

Use Bootstrap 5 classes and components

Create a button that toggles horizontal collapse

Create a collapsible content area that expands horizontally

Ensure the collapse works smoothly on button click

Use semantic HTML and accessible attributes

💡 Why This Matters

🌍 Real World

Horizontal collapsible sections are common in navigation menus, sidebars, and interactive panels on websites and web apps.

💼 Career

Knowing how to implement Bootstrap's collapse component helps you build responsive, user-friendly interfaces quickly, a valuable skill for frontend web development jobs.

1

Set up the basic HTML structure with Bootstrap

Create a basic HTML5 page with lang="en", meta charset="UTF-8", and viewport meta tag. Include Bootstrap 5 CSS from CDN inside the <head>. Inside the <body>, add a <div> with class container and inside it add a <button> with id="toggleButton" and text Toggle Horizontal Collapse.

Bootsrap

Hint

Remember to include Bootstrap CSS from CDN inside the <head>. Add a button inside a container with the exact id="toggleButton" and text.

2

Add the collapsible content container

Below the <button id="toggleButton">, add a <div> with id="collapseContent" and classes collapse collapse-horizontal border bg-light p-3 mt-3. Inside this div, add the text Here is the horizontally collapsible content!.

Bootsrap

    
    
    
    Horizontal Collapse


    
        Toggle Horizontal Collapse
        
    

Hint

Use the Bootstrap classes collapse and collapse-horizontal on the content div. Add some border and padding for better visibility.

3

Add the button attributes to toggle the collapse

Add the attributes data-bs-toggle="collapse" and data-bs-target="#collapseContent" to the <button id="toggleButton"> so it toggles the horizontal collapse on click.

Bootsrap

    
    
    
    Horizontal Collapse


    
        
        >Toggle Horizontal Collapse
        
            Here is the horizontally collapsible content!
        
    

Hint

Add data-bs-toggle="collapse" and data-bs-target="#collapseContent" to the button. Also add accessibility attributes aria-expanded="false" and aria-controls="collapseContent".

4

Include Bootstrap JavaScript for collapse functionality

Before the closing </body> tag, add the Bootstrap 5 JavaScript bundle CDN script tag: <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/js/bootstrap.bundle.min.js"></script>. This enables the collapse toggle to work.

Bootsrap

    
    
    
    Horizontal Collapse


    
        Toggle Horizontal Collapse
        
            Here is the horizontally collapsible content!
        
    
    

Hint

Include the Bootstrap JavaScript bundle before the closing </body> tag to enable interactive components like collapse.

Practice

1. What does the collapse-horizontal class do in Bootstrap?

easy

A. It makes the collapsible content slide left or right instead of up or down.

B. It changes the color of the collapsible content.

C. It disables the collapse functionality.

D. It makes the collapsible content slide up or down.

Solution

1. Step 1: Understand the role of collapse-horizontal

   This class changes the collapse animation direction from vertical (up/down) to horizontal (left/right).

2. Step 2: Compare with default collapse behavior

   By default, Bootstrap collapses content vertically. Adding collapse-horizontal changes this to horizontal sliding.

3. Final Answer:

   It makes the collapsible content slide left or right instead of up or down. -> Option A

4. Quick Check:

   collapse-horizontal = horizontal slide [OK]

Hint: Remember: horizontal means left-right slide, not up-down [OK]

Common Mistakes:

• Thinking it changes color or disables collapse
• Confusing horizontal with vertical collapse
• Assuming it works without Bootstrap JS

2. Which of the following is the correct way to start a horizontal collapse in Bootstrap?

easy

A. <div class='collapse-vertical' id='myCollapse'></div>

B. <div class='horizontal-collapse' id='myCollapse'></div>

C. <div class='collapse-horizontal'></div>

D. <div class='collapse collapse-horizontal' id='myCollapse'></div>

Solution

1. Step 1: Identify correct Bootstrap classes for horizontal collapse

   The correct classes are collapse and collapse-horizontal together on the element.

2. Step 2: Check the syntax of options

   <div class='collapse collapse-horizontal' id='myCollapse'></div> uses both classes and includes an id for toggling, which is required for Bootstrap collapse to work.

3. Final Answer:

   <div class='collapse collapse-horizontal' id='myCollapse'></div> -> Option D

4. Quick Check:

   Use both collapse and collapse-horizontal classes [OK]

Hint: Always combine collapse with collapse-horizontal for horizontal effect [OK]

Common Mistakes:

• Using only collapse-horizontal without collapse
• Using wrong class names like collapse-vertical
• Missing the id attribute for toggling

3. Given this code snippet, what will happen when the button is clicked?

<button class='btn btn-primary' type='button' data-bs-toggle='collapse' data-bs-target='#collapseExample'>Toggle</button>
<div class='collapse collapse-horizontal' id='collapseExample' style='width: 200px;'>Content</div>

medium

A. The content slides vertically, expanding or collapsing height.

B. The content slides horizontally, expanding or collapsing width.

C. Nothing happens because width is set inline.

D. The button causes a page reload.

Solution

1. Step 1: Analyze the collapse classes and attributes

   The div has collapse and collapse-horizontal classes, so it will collapse horizontally.

2. Step 2: Understand the effect of inline width

   The inline style sets width to 200px, which is necessary for horizontal collapse to know the size to expand or collapse.

3. Final Answer:

   The content slides horizontally, expanding or collapsing width. -> Option B

4. Quick Check:

   collapse-horizontal + width = horizontal slide [OK]

Hint: Horizontal collapse needs width set to animate properly [OK]

Common Mistakes:

• Assuming vertical slide happens by default
• Thinking inline width disables collapse
• Expecting page reload on button click

4. What is wrong with this horizontal collapse code?

<div class='collapse-horizontal' id='myCollapse'>Content</div>
<button data-bs-toggle='collapse' data-bs-target='#myCollapse'>Toggle</button>

medium

A. Missing the main collapse class on the div.

B. Button is missing the type='button' attribute.

C. The id attribute should be on the button, not the div.

D. The collapse-horizontal class should be on the button.

Solution

1. Step 1: Check required classes for collapse

   Bootstrap requires the collapse class on the collapsible element for functionality.

2. Step 2: Identify missing class in code

   The div only has collapse-horizontal but lacks collapse, so it won't collapse properly.

3. Final Answer:

   Missing the main collapse class on the div. -> Option A

4. Quick Check:

   collapse class is mandatory for collapse [OK]

Hint: Always include collapse class with collapse-horizontal [OK]

Common Mistakes:

• Forgetting the collapse class
• Misplacing id attribute
• Assuming button needs collapse-horizontal

5. You want to create a horizontal collapse panel that starts collapsed and expands to 300px wide when toggled. Which code snippet correctly achieves this with accessibility in mind?

hard

A. <button class='btn btn-info' type='button' data-bs-toggle='collapse' data-bs-target='#panel'>Toggle Panel</button>
<div class='collapse collapse-horizontal' id='panel' style='height: 300px;'>Panel Content</div>

B. <button class='btn btn-info' data-toggle='collapse' data-target='#panel'>Toggle Panel</button>
<div class='collapse-horizontal' id='panel' style='width: 300px;'>Panel Content</div>

C. <button class='btn btn-info' type='button' data-bs-toggle='collapse' data-bs-target='#panel' aria-expanded='false' aria-controls='panel'>Toggle Panel</button>
<div class='collapse collapse-horizontal' id='panel' style='width: 300px;'>Panel Content</div>

D. <button class='btn btn-info' type='button' data-bs-toggle='collapse' data-bs-target='#panel' aria-expanded='true' aria-controls='panel'>Toggle Panel</button>
<div class='collapse collapse-horizontal' id='panel' style='width: 300px;'>Panel Content</div>

Solution

1. Step 1: Check button attributes for accessibility

   <button class='btn btn-info' type='button' data-bs-toggle='collapse' data-bs-target='#panel' aria-expanded='false' aria-controls='panel'>Toggle Panel</button>
   <div class='collapse collapse-horizontal' id='panel' style='width: 300px;'>Panel Content</div>

   includes aria-expanded='false' and aria-controls='panel', which help screen readers understand the toggle state.

2. Step 2: Verify collapse classes and styles

   The div has both collapse and collapse-horizontal classes and sets width to 300px, which is correct for horizontal collapse.

3. Final Answer:

   <button class='btn btn-info' type='button' data-bs-toggle='collapse' data-bs-target='#panel' aria-expanded='false' aria-controls='panel'>Toggle Panel</button> <div class='collapse collapse-horizontal' id='panel' style='width: 300px;'>Panel Content</div> -> Option C

4. Quick Check:

   Use aria attributes + collapse + collapse-horizontal + width [OK]

Hint: Add aria-expanded and aria-controls for accessible toggles [OK]

Common Mistakes:

• Using data-toggle instead of data-bs-toggle
• Setting height instead of width for horizontal collapse
• Missing aria attributes for accessibility