Collapse toggle via JavaScript in Bootsrap - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to select the collapse element by its ID.

Bootsrap

const collapseElement = document.querySelector('[1]');

Drag options to blanks, or click blank then click option'

AmyCollapse

B#myCollapse

Ccollapse

D.collapse

Attempts:

3 left

💡 Hint

Common Mistakes

Using the ID name without '#' like 'myCollapse' which does not select the element.

Using a class selector '.' when the element has an ID.

The querySelector method requires a CSS selector string. To select an element by ID, prefix the ID with #. So #myCollapse selects the element with ID myCollapse.

2fill in blank

medium

Complete the code to create a Bootstrap Collapse instance for the element.

Bootsrap

const bsCollapse = new bootstrap.Collapse([1]);

Drag options to blanks, or click blank then click option'

Adocument.querySelector('.collapse')

Bdocument.getElementById('myCollapse')

C'#myCollapse'

DcollapseElement

Attempts:

3 left

💡 Hint

Common Mistakes

Passing a selector string like '#myCollapse' instead of the element.

Passing a method call instead of the stored element variable.

The Bootstrap Collapse constructor expects a DOM element, not a selector string. Since collapseElement already holds the element, pass it directly.

3fill in blank

hard

Fix the error in the code to toggle the collapse using the Bootstrap instance.

Bootsrap

bsCollapse.[1]();

Drag options to blanks, or click blank then click option'

Ashow

Bhide

Ctoggle

Dcollapse

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'show' or 'hide' which only do one action, not toggle.

Using a non-existent method like 'collapse'.

The toggle() method switches the collapse state between shown and hidden. Using show() or hide() only shows or hides respectively, but toggle is needed to switch.

4fill in blank

hard

Fill both blanks to add a click event listener to the button that toggles the collapse.

Bootsrap

document.querySelector('[1]').addEventListener('[2]', () => {
  bsCollapse.toggle();
});

Drag options to blanks, or click blank then click option'

A#toggleButton

Bclick

Cmouseover

D#myCollapse

Attempts:

3 left

💡 Hint

Common Mistakes

Selecting the collapse element instead of the button.

Using 'mouseover' event instead of 'click'.

The button to toggle the collapse has ID 'toggleButton', so select it with '#toggleButton'. The event to listen for is a 'click' to trigger the toggle.

5fill in blank

hard

Fill all three blanks to create a complete toggle setup: select button, add click event, and toggle collapse.

Bootsrap

const btn = document.querySelector('[1]');
btn.addEventListener('[2]', () => {
  bsCollapse.[3]();
});

Drag options to blanks, or click blank then click option'

A#toggleBtn

Bclick

Ctoggle

D#collapseExample

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong selectors like '#collapseExample' for the button.

Using wrong event types like 'mouseover'.

Calling methods other than 'toggle()' to switch collapse.

We select the button with ID 'toggleBtn' using '#toggleBtn'. We listen for the 'click' event. On click, we call the toggle() method on the Bootstrap collapse instance to switch its state.

Practice

1. What does the toggle() method do when used with new bootstrap.Collapse(element) in Bootstrap?

easy

A. It reloads the entire page.

B. It shows the hidden content if collapsed, or hides it if shown.

C. It permanently disables the collapse functionality.

D. It changes the color of the collapsed content.

Solution

1. Step 1: Understand the collapse object

   The new bootstrap.Collapse(element) creates a controller for the collapsible content.

2. Step 2: Role of toggle() method

   The toggle() method switches the content between visible and hidden states smoothly.

3. Final Answer:

   It shows the hidden content if collapsed, or hides it if shown. -> Option B

4. Quick Check:

   toggle() switches collapse state [OK]

Hint: toggle() flips collapse open or closed [OK]

Common Mistakes:

• Thinking toggle disables collapse
• Confusing toggle with page reload
• Assuming toggle changes styles only

2. Which of the following is the correct way to create a Bootstrap collapse instance for an element with id myCollapse in JavaScript?

easy

A. const collapse = new bootstrap.Collapse('myCollapse');

B. const collapse = bootstrap.Collapse('#myCollapse');

C. const collapse = new bootstrap.Collapse(document.getElementById('myCollapse'));

D. const collapse = new Collapse('myCollapse');

Solution

1. Step 1: Identify the element reference

   The Bootstrap Collapse constructor requires a DOM element, not a selector string.

2. Step 2: Correct syntax for element selection

   Using document.getElementById('myCollapse') returns the element to pass to the constructor.

3. Final Answer:

   const collapse = new bootstrap.Collapse(document.getElementById('myCollapse')); -> Option C

4. Quick Check:

   Pass DOM element, not selector string [OK]

Hint: Use getElementById to pass element, not string [OK]

Common Mistakes:

• Passing selector string instead of element
• Omitting 'new' keyword
• Using undefined Collapse without bootstrap prefix

3. Given the following code, what will be the visible state of the collapsible content after the button is clicked once?

const collapse = new bootstrap.Collapse(document.getElementById('content'), { toggle: false });
document.getElementById('toggleBtn').addEventListener('click', () => {
  collapse.toggle();
});

The content is initially hidden.

medium

A. The content will become visible.

B. The content will remain hidden.

C. The content will be removed from the DOM.

D. An error will occur because toggle is false.

Solution

1. Step 1: Understand initial state and options

   The content starts hidden and toggle: false means it won't auto-toggle on creation.

2. Step 2: Effect of calling toggle() on click

   Calling toggle() manually switches the state, so hidden content becomes visible.

3. Final Answer:

   The content will become visible. -> Option A

4. Quick Check:

   Manual toggle() shows hidden content [OK]

Hint: toggle() always flips visibility regardless of options [OK]

Common Mistakes:

• Thinking toggle:false disables toggle() method
• Assuming content stays hidden without auto toggle
• Confusing toggle() with remove()

4. Identify the error in this code snippet that tries to toggle a Bootstrap collapse:

const collapse = new bootstrap.Collapse('content');
document.getElementById('btn').addEventListener('click', () => {
  collapse.toggle();
});

medium

A. The selector 'content' should be a DOM element, not a string.

B. The toggle() method is not available on collapse instances.

C. The event listener is attached to the wrong element.

D. Missing parentheses when calling toggle.

Solution

1. Step 1: Check constructor argument

   The constructor expects a DOM element, but 'content' is a string selector, which is incorrect.

2. Step 2: Correct way to pass element

   Use document.getElementById('content') to get the element before passing it.

3. Final Answer:

   The selector 'content' should be a DOM element, not a string. -> Option A

4. Quick Check:

   Pass DOM element, not string selector [OK]

Hint: Always pass DOM element, not string selector [OK]

Common Mistakes:

• Passing string selector instead of element
• Assuming toggle() is unavailable
• Incorrect event listener target

5. You want to toggle a Bootstrap collapse and update the button text between 'Show' and 'Hide' accordingly. Which JavaScript code correctly achieves this?

const collapse = new bootstrap.Collapse(document.getElementById('panel'), { toggle: false });
const btn = document.getElementById('toggleBtn');
btn.addEventListener('click', () => {
  collapse.toggle();
  if (btn.textContent === 'Show') {
    btn.textContent = 'Hide';
  } else {
    btn.textContent = 'Show';
  }
});

hard

A. The collapse instance must be recreated inside the click event.

B. The button text update should happen before calling toggle().

C. You must use btn.innerHTML instead of textContent.

D. This code works correctly to toggle and update button text.

Solution

1. Step 1: Check toggle and button text update order

   The code calls collapse.toggle() then updates the button text based on current text, which is logical.

2. Step 2: Validate textContent usage and event setup

   Using textContent is correct for plain text updates, and the collapse instance is created once outside the event.

3. Final Answer:

   This code works correctly to toggle and update button text. -> Option D

4. Quick Check:

   Toggle then update textContent works [OK]

Hint: Toggle first, then update button text [OK]

Common Mistakes:

• Updating text before toggle causing mismatch
• Using innerHTML unnecessarily
• Recreating collapse instance on every click