Accordion component in Bootsrap

Introduction

An accordion helps show or hide sections of content on a page. It keeps the page neat and easy to read.

You want to organize FAQs so users can open one question at a time.

You have a long list of items and want to save space by hiding details.

You want to let users expand or collapse sections without leaving the page.

You want a simple way to show multiple content panels but only one open at a time.

Syntax

Bootsrap

<div class="accordion" id="accordionExample">
  <div class="accordion-item">
    <h2 class="accordion-header" id="headingOne">
      <button class="accordion-button" type="button" data-bs-toggle="collapse" data-bs-target="#collapseOne" aria-expanded="true" aria-controls="collapseOne">
        Accordion Item #1
      </button>
    </h2>
    <div id="collapseOne" class="accordion-collapse collapse show" aria-labelledby="headingOne" data-bs-parent="#accordionExample">
      <div class="accordion-body">
        Content for the first accordion item.
      </div>
    </div>
  </div>
  <!-- Repeat accordion-item blocks for more items -->
</div>

Use data-bs-toggle="collapse" on the button to make it open or close the content.

The data-bs-parent attribute makes sure only one item is open at a time.

Examples

This example shows a single accordion item open by default using collapse show.

Bootsrap

<div class="accordion" id="accordionExample">
  <div class="accordion-item">
    <h2 class="accordion-header" id="headingOne">
      <button class="accordion-button" type="button" data-bs-toggle="collapse" data-bs-target="#collapseOne" aria-expanded="true" aria-controls="collapseOne">
        First Item
      </button>
    </h2>
    <div id="collapseOne" class="accordion-collapse collapse show" aria-labelledby="headingOne" data-bs-parent="#accordionExample">
      <div class="accordion-body">
        This is the first item's content.
      </div>
    </div>
  </div>
</div>

This example shows an accordion item closed by default with the button having the collapsed class.

Bootsrap

<div class="accordion" id="accordionExample">
  <div class="accordion-item">
    <h2 class="accordion-header" id="headingTwo">
      <button class="accordion-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseTwo" aria-expanded="false" aria-controls="collapseTwo">
        Second Item
      </button>
    </h2>
    <div id="collapseTwo" class="accordion-collapse collapse" aria-labelledby="headingTwo" data-bs-parent="#accordionExample">
      <div class="accordion-body">
        Content for the second item, hidden initially.
      </div>
    </div>
  </div>
</div>

Sample Program

This complete example shows a Bootstrap accordion with three items. The first item is open by default. Clicking on each header toggles its content. Only one item can be open at a time.

Bootsrap

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8" />
  <meta name="viewport" content="width=device-width, initial-scale=1" />
  <title>Bootstrap Accordion Example</title>
  <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/css/bootstrap.min.css" rel="stylesheet" />
</head>
<body>
  <main class="container my-5">
    <h1>Simple Accordion</h1>
    <div class="accordion" id="accordionExample">
      <div class="accordion-item">
        <h2 class="accordion-header" id="headingOne">
          <button class="accordion-button" type="button" data-bs-toggle="collapse" data-bs-target="#collapseOne" aria-expanded="true" aria-controls="collapseOne">
            What is an accordion?
          </button>
        </h2>
        <div id="collapseOne" class="accordion-collapse collapse show" aria-labelledby="headingOne" data-bs-parent="#accordionExample">
          <div class="accordion-body">
            An accordion is a UI component that lets you expand and collapse sections of content.
          </div>
        </div>
      </div>
      <div class="accordion-item">
        <h2 class="accordion-header" id="headingTwo">
          <button class="accordion-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseTwo" aria-expanded="false" aria-controls="collapseTwo">
            Why use an accordion?
          </button>
        </h2>
        <div id="collapseTwo" class="accordion-collapse collapse" aria-labelledby="headingTwo" data-bs-parent="#accordionExample">
          <div class="accordion-body">
            It helps keep pages clean by hiding content until the user wants to see it.
          </div>
        </div>
      </div>
      <div class="accordion-item">
        <h2 class="accordion-header" id="headingThree">
          <button class="accordion-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseThree" aria-expanded="false" aria-controls="collapseThree">
            How to use it?
          </button>
        </h2>
        <div id="collapseThree" class="accordion-collapse collapse" aria-labelledby="headingThree" data-bs-parent="#accordionExample">
          <div class="accordion-body">
            Use Bootstrap classes and data attributes to create the accordion structure and behavior.
          </div>
        </div>
      </div>
    </div>
  </main>
  <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/js/bootstrap.bundle.min.js"></script>
</body>
</html>

Important Notes

Always include aria-expanded and aria-controls for accessibility.

Use the Bootstrap JavaScript bundle to enable the accordion's interactive behavior.

The data-bs-parent attribute ensures only one accordion item is open at a time.

Summary

An accordion shows or hides content sections to keep pages tidy.

Bootstrap uses specific classes and data attributes to create accordions easily.

Accessibility attributes help screen readers understand the accordion's state.

Practice

1. What is the main purpose of the Accordion component in Bootstrap?

easy

A. To create a navigation bar with dropdown menus

B. To show and hide sections of content by expanding or collapsing them

C. To display images in a sliding carousel

D. To style buttons with different colors

Solution

1. Step 1: Understand Accordion functionality

   The Accordion component is designed to toggle visibility of content sections by expanding or collapsing them.

2. Step 2: Compare with other Bootstrap components

   Navigation bars, carousels, and buttons serve different purposes unrelated to content toggling.

3. Final Answer:

   To show and hide sections of content by expanding or collapsing them -> Option B

4. Quick Check:

   Accordion = toggle content visibility [OK]

Hint: Accordion toggles content sections open or closed [OK]

Common Mistakes:

• Confusing Accordion with navigation menus
• Thinking Accordion is for image sliders
• Assuming Accordion styles buttons

2. Which of the following is the correct HTML structure to start an Accordion in Bootstrap 5?

easy

A. <div class='accordion' id='myAccordion'>

B. <accordion id='myAccordion'>

C. <div class='accordion-item'>

D. <section class='accordion-collapse'>

Solution

1. Step 1: Identify the container element for Accordion

   The Accordion container uses a div with class accordion and an ID for reference.

2. Step 2: Check Bootstrap 5 syntax

   Bootstrap 5 requires div.accordion as the wrapper, not accordion tag or other classes like accordion-item or accordion-collapse alone.

3. Final Answer:

   <div class='accordion' id='myAccordion'> -> Option A

4. Quick Check:

   Accordion container = div.accordion [OK]

Hint: Accordion always starts with div.accordion container [OK]

Common Mistakes:

• Using a non-existent <accordion> tag
• Starting with accordion-item instead of accordion container
• Confusing collapse section with container

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

<div class='accordion-item'>
  <h2 class='accordion-header' id='headingOne'>
    <button class='accordion-button' type='button' data-bs-toggle='collapse' data-bs-target='#collapseOne' aria-expanded='true' aria-controls='collapseOne'>
      Section 1
    </button>
  </h2>
  <div id='collapseOne' class='accordion-collapse collapse show' aria-labelledby='headingOne' data-bs-parent='#myAccordion'>
    <div class='accordion-body'>Content 1</div>
  </div>
</div>

medium

A. The entire accordion will reload the page

B. Nothing will happen because the button lacks a click event

C. The content inside 'Content 1' will collapse or expand when the button is clicked

D. The button will change color but content stays visible

Solution

1. Step 1: Analyze button attributes for toggle

   The button has data-bs-toggle='collapse' and data-bs-target='#collapseOne', linking it to the collapsible content.

2. Step 2: Check the collapsible content state

   The content div has class collapse show, meaning it is visible initially and will toggle on button click.

3. Final Answer:

   The content inside 'Content 1' will collapse or expand when the button is clicked -> Option C

4. Quick Check:

   Button toggles collapse content visibility [OK]

Hint: data-bs-toggle='collapse' toggles content visibility [OK]

Common Mistakes:

• Assuming button does nothing without explicit JS
• Thinking button reloads page
• Confusing color change with content toggle

4. What is wrong with this Accordion code snippet that prevents it from working properly?

<div class='accordion' id='accordionExample'>
  <div class='accordion-item'>
    <h2 class='accordion-header' id='headingOne'>
      <button class='accordion-button' type='button' data-bs-toggle='collapse' data-bs-target='#collapseOne' aria-expanded='false' aria-controls='collapseOne'>
        Accordion Item #1
      </button>
    </h2>
    <div id='collapseOne' class='accordion-collapse' aria-labelledby='headingOne' data-bs-parent='#accordionExample'>
      <div class='accordion-body'>Content for item 1</div>
    </div>
  </div>
</div>

medium

A. The accordion-collapse div is missing the collapse class

B. The button should not have aria-expanded attribute

C. The data-bs-parent attribute should be on the button, not the collapse div

D. The accordion container is missing an ID

Solution

1. Step 1: Check classes on collapsible content

   The collapsible div must have class collapse to enable Bootstrap's collapse behavior.

2. Step 2: Verify other attributes

   The aria-expanded attribute on the button is correct and data-bs-parent belongs on the collapse div. The container has an ID.

3. Final Answer:

   The accordion-collapse div is missing the collapse class -> Option A

4. Quick Check:

   collapse class missing = no toggle [OK]

Hint: Always add 'collapse' class to collapsible content div [OK]

Common Mistakes:

• Forgetting the 'collapse' class on content div
• Misplacing data-bs-parent attribute
• Removing aria-expanded attribute

5. You want to create an Accordion where only one section can be open at a time, and the first section is open by default. Which combination of attributes and classes achieves this behavior correctly?

hard

A. Add data-bs-single='true' to buttons and expanded attribute on first button

B. Add data-bs-toggle='accordion' to buttons and active class to first button

C. Use data-bs-multiple='false' on accordion container and open class on first item

D. Add data-bs-parent to each collapse div and add show class to the first collapse div

Solution

1. Step 1: Understand Bootstrap's single-open behavior

   Bootstrap uses data-bs-parent on collapse divs to ensure only one section is open at a time.

2. Step 2: Set default open section

   Adding the show class to the first collapse div makes it open by default on page load.

3. Step 3: Evaluate other options

   Attributes like data-bs-toggle='accordion', data-bs-multiple, or data-bs-single do not exist in Bootstrap 5 for this purpose.

4. Final Answer:

   Add data-bs-parent to each collapse div and add show class to the first collapse div -> Option D

5. Quick Check:

   data-bs-parent + show class = single open with default [OK]

Hint: Use data-bs-parent and show class for single open accordion [OK]

Common Mistakes:

• Using non-existent Bootstrap attributes
• Forgetting to add show class for default open
• Misplacing data-bs-parent attribute