Checkboxes and radios in Bootsrap - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

What is the purpose of the name attribute in a group of radio buttons?

In Bootstrap forms, why do all radio buttons in the same group share the same name attribute?

A It makes the radio buttons larger and easier to click.

B It disables all radio buttons in the group.

C It styles the radio buttons with Bootstrap colors.

D It groups the radio buttons so only one can be selected at a time.

💡 Hint

Think about how radio buttons behave when grouped.

The name attribute groups radio buttons so that only one button in that group can be selected at a time. This is standard HTML behavior and Bootstrap uses it as well.

📝 Syntax

intermediate

Which option correctly creates a Bootstrap styled checkbox?

Select the correct Bootstrap 5 checkbox code snippet that will render a checkbox with label "Subscribe".

A

<div class="checkbox">
  <input type="checkbox" id="subscribeCheck">
  <label>Subscribe</label>
</div>

B

<div class="form-check">
  <input class="form-check-input" type="checkbox" id="subscribeCheck">
  <label class="form-check-label" for="subscribeCheck">Subscribe</label>
</div>

C

<input type="checkbox" class="checkbox" id="subscribeCheck">
<label for="subscribeCheck">Subscribe</label>

D

<div class="form-group">
  <input type="checkbox" class="form-control" id="subscribeCheck">
  <label for="subscribeCheck">Subscribe</label>
</div>

💡 Hint

Bootstrap checkboxes use form-check and form-check-input classes.

Bootstrap 5 requires wrapping the checkbox input in a div with class form-check. The input uses class form-check-input and the label uses form-check-label with a matching for attribute.

❓ rendering

advanced

What will be the visual result of this Bootstrap radio button code?

Given the following code, what will the user see in the browser?

Bootsrap

<div class="form-check">
  <input class="form-check-input" type="radio" name="colorOptions" id="redOption" value="red" checked>
  <label class="form-check-label" for="redOption">Red</label>
</div>
<div class="form-check">
  <input class="form-check-input" type="radio" name="colorOptions" id="blueOption" value="blue">
  <label class="form-check-label" for="blueOption">Blue</label>
</div>

A Two radio buttons labeled 'Red' and 'Blue', with 'Red' selected by default.

B Two checkboxes labeled 'Red' and 'Blue', both unchecked.

C Two radio buttons labeled 'Red' and 'Blue', both selected.

D A dropdown menu with options 'Red' and 'Blue'.

💡 Hint

Look at the type and checked attributes.

The code creates two radio buttons with the same name, so only one can be selected. The 'Red' option has the checked attribute, so it is selected by default.

❓ selector

advanced

Which CSS selector correctly targets only checked Bootstrap checkboxes?

You want to style only the checkboxes that are checked in a Bootstrap form. Which CSS selector will do this?

A input.form-check-input[type="checkbox"]:checked + label.form-check-label

B input[type="checkbox"]:checked

C .form-check-input:checked

D label.form-check-label:checked

💡 Hint

Remember the label is a sibling after the input.

Bootstrap checkboxes have the input and label as siblings inside div.form-check. To style the label when the checkbox is checked, use the adjacent sibling selector + label.form-check-label after the checked input.

❓ accessibility

expert

Which practice improves accessibility for Bootstrap radio buttons?

To make Bootstrap radio buttons accessible for screen readers and keyboard users, which practice is best?

A Wrap radio inputs inside <code>div</code> without labels and use placeholder text.

B Add <code>aria-hidden="true"</code> to all radio inputs.

C Use <code>label</code> elements with <code>for</code> attributes matching the input <code>id</code>.

D Use only colors to indicate which radio button is selected.

💡 Hint

Think about how screen readers identify form controls.

Associating label elements with inputs via matching for and id attributes helps screen readers announce the label when the input is focused. This is essential for accessibility.

Practice

1. What is the main difference between checkboxes and radio buttons in Bootstrap forms?

easy

A. Radios can be unchecked by clicking again; checkboxes cannot.

B. Checkboxes allow multiple selections; radios allow only one selection.

C. Checkboxes are styled differently but behave the same as radios.

D. Checkboxes allow only one selection; radios allow multiple selections.

Solution

1. Step 1: Understand checkbox behavior

   Checkboxes let users pick more than one option at the same time.

2. Step 2: Understand radio button behavior

   Radio buttons let users pick only one option from a group.

3. Final Answer:

   Checkboxes allow multiple selections; radios allow only one selection. -> Option B

4. Quick Check:

   Checkboxes = multiple, Radios = single [OK]

Hint: Checkboxes = many choices, radios = one choice [OK]

Common Mistakes:

• Confusing which input allows multiple selections
• Thinking radios can be unchecked by clicking again
• Assuming checkboxes behave like radios

2. Which of the following is the correct Bootstrap structure for a single checkbox input with label?

easy

A. Option 1

B. Option 1

C. Option 1

D. Option 1

Solution

1. Step 1: Check input and label classes

   Bootstrap requires form-check-input on the input and form-check-label on the label.

2. Step 2: Verify input type and id-label connection

   The input must be type checkbox and the label's for attribute must match input's id.

3. Final Answer:

   Option A has correct classes, input type, and label connection. -> Option A

4. Quick Check:

   Correct classes and matching id-for =
   Option 1 [OK]

Hint: Input uses form-check-input; label uses form-check-label [OK]

Common Mistakes:

• Swapping classes between input and label
• Using wrong input type for checkbox
• Not matching label's for attribute with input id

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

<div class='form-check'>
  <input class='form-check-input' type='radio' name='color' id='red' checked>
  <label class='form-check-label' for='red'>Red</label>
</div>
<div class='form-check'>
  <input class='form-check-input' type='radio' name='color' id='blue'>
  <label class='form-check-label' for='blue'>Blue</label>
</div>

medium

A. Two checkboxes labeled Red and Blue; Blue is selected by default.

B. Two radio buttons labeled Red and Blue; none selected by default.

C. Two radio buttons labeled Red and Blue; Red is selected by default.

D. Two checkboxes labeled Red and Blue; Red is selected by default.

Solution

1. Step 1: Identify input types and attributes

   Both inputs are radio buttons with the same name 'color', so only one can be selected.

2. Step 2: Check which radio is checked by default

   The input with id 'red' has the checked attribute, so it is selected initially.

3. Final Answer:

   Two radio buttons labeled Red and Blue; Red is selected by default. -> Option C

4. Quick Check:

   Radio with checked attribute = selected [OK]

Hint: Look for checked attribute on radio inputs [OK]

Common Mistakes:

• Confusing radio buttons with checkboxes
• Ignoring the checked attribute
• Assuming multiple radios can be selected

4. Identify the error in this Bootstrap checkbox code:

<div class='form-check'>
  <input class='form-check-input' type='checkbox' id='agree'>
  <label class='form-check-label' id='agree'>I agree</label>
</div>

medium

A. The input type should be radio, not checkbox.

B. The input is missing the class form-check-label.

C. The div should have class form-check-input instead of form-check.

D. The label uses id instead of for attribute to link to input.

Solution

1. Step 1: Check label linkage to input

   Labels must use the for attribute matching the input's id for accessibility and clicking.

2. Step 2: Identify incorrect attribute usage

   The label incorrectly uses id='agree' instead of for='agree'.

3. Final Answer:

   The label uses id instead of for attribute to link to input. -> Option D

4. Quick Check:

   Label uses for, not id, to link input [OK]

Hint: Label must use for attribute matching input id [OK]

Common Mistakes:

• Using id on label instead of for
• Missing form-check-input class on input
• Confusing input types checkbox vs radio

5. You want to create a group of checkboxes in Bootstrap where users can select multiple fruits. Which code snippet correctly implements this with accessible labels and Bootstrap styling?

hard

A. \n \n Apple\n\n\n \n Banana\n

B. \n \n Apple\n\n\n \n Banana\n

C. \n \n Apple\n\n\n \n Banana\n

D. \n \n Apple\n\n\n \n Banana\n

Solution

1. Step 1: Confirm input types for multiple selection

   Checkboxes allow multiple selections, so input type must be checkbox.

2. Step 2: Check label and input classes and attributes

   Inputs must have class form-check-input, labels must have form-check-label, and labels must use for matching input id.

3. Step 3: Verify unique ids and consistent names

   Each checkbox has a unique id and the same name attribute to group them logically.

4. Final Answer:

   Option A correctly uses checkboxes with proper classes, unique ids, and accessible labels. -> Option A

5. Quick Check:

   Checkboxes + form-check-input + matching for/id =
   \n \n Apple\n\n

   \n \n Banana\n

   [OK]

Hint: Use checkbox type and matching for/id for labels [OK]

Common Mistakes:

• Using radio buttons instead of checkboxes for multiple choices
• Repeating ids for different inputs
• Swapping input and label classes