Checkboxes and radios in Bootsrap - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main difference between a checkbox and a radio button?

A checkbox allows selecting multiple options at once, while a radio button allows selecting only one option from a group.

beginner

How do you group radio buttons so only one can be selected at a time?

Give all radio buttons the same name attribute value to group them together.

beginner

In Bootstrap, which class is used to style a checkbox or radio button?

Use the <code>.form-check</code> class on a container and <code>.form-check-input</code> on the input element.

intermediate

How can you make a checkbox or radio button disabled in Bootstrap?

Add the <code>disabled</code> attribute to the input element and optionally add the <code>.disabled</code> class to the label.

beginner

Why is it important to use labels with checkboxes and radio buttons?

Labels improve accessibility by making the clickable area larger and helping screen readers identify the input purpose.

Which Bootstrap class should you add to the input element of a checkbox?

A .input-checkbox

B .form-check-input

C .checkbox-input

D .form-control

Bootstrap uses the .form-check-input class to style checkbox and radio inputs.

How do you ensure only one radio button can be selected in a group?

A Give all radio buttons the same name

B Give all radio buttons the same id

C Wrap them in a <div>

D Add the disabled attribute

Radio buttons with the same name attribute belong to one group and only one can be selected.

What attribute disables a checkbox or radio button?

A disabled

B block

C inactive

D readonly

The disabled attribute makes the input unclickable and grayed out.

Why should you always use a <label> with checkboxes and radios?

A To make inputs bigger

B To add color

C To increase clickable area and improve accessibility

D To disable inputs

Labels link text to inputs, making them easier to use and accessible for screen readers.

Which container class wraps a checkbox or radio in Bootstrap?

A .form-group

B .form-control

C .input-group

D .form-check

The .form-check class is used to wrap checkboxes and radios for proper Bootstrap styling.

Explain how to create a group of radio buttons in Bootstrap that allows only one selection.

Think about grouping and styling with Bootstrap classes.

Describe why labels are important for checkboxes and radio buttons and how to connect them properly.

Consider users who rely on keyboard or screen readers.

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