Modal sizes and positioning in Bootsrap - Cheat Sheet & Quick Revision

Recall & Review

beginner

What class in Bootstrap controls the size of a modal?

Bootstrap uses classes like modal-sm, modal-lg, and modal-xl on the .modal-dialog element to control modal sizes.

beginner

How do you center a Bootstrap modal vertically?

Add the class modal-dialog-centered to the .modal-dialog element to vertically center the modal in the viewport.

intermediate

Which Bootstrap class makes a modal full screen on all devices?

Use the class modal-fullscreen on the .modal-dialog element to make the modal cover the entire screen.

beginner

What is the default horizontal alignment of a Bootstrap modal?

By default, Bootstrap modals are horizontally centered in the viewport without extra classes.

intermediate

How can you make a modal scrollable if its content is too tall?

Add the class modal-dialog-scrollable to the .modal-dialog element to enable vertical scrolling inside the modal body.

Which class would you add to make a Bootstrap modal larger than the default size?

A modal-lg

B modal-center

C modal-small

D modal-fullscreen

The class modal-lg makes the modal larger than the default size.

How do you vertically center a Bootstrap modal?

A Add <code>modal-center</code> to <code>.modal</code>

B Add <code>modal-dialog-centered</code> to <code>.modal-dialog</code>

C Add <code>centered</code> to <code>.modal-content</code>

D Add <code>modal-vertical</code> to <code>.modal-dialog</code>

The class modal-dialog-centered vertically centers the modal.

Which class makes a Bootstrap modal take up the entire screen?

A modal-lg

B modal-xl

C modal-fullscreen

D modal-scrollable

modal-fullscreen makes the modal cover the full screen.

If modal content is too tall, which class helps to scroll inside the modal?

A modal-dialog-scrollable

B modal-scroll

C modal-scrollbar

D modal-content-scroll

Use modal-dialog-scrollable to enable scrolling inside the modal.

What is the default horizontal alignment of Bootstrap modals?

A Top aligned

B Aligned left

C Aligned right

D Centered horizontally

Bootstrap modals are horizontally centered by default.

Explain how to change the size of a Bootstrap modal and give examples of classes used.

Think about classes added to the modal dialog to control width.

Describe how to position a Bootstrap modal vertically centered and how to handle tall content inside it.

Consider classes that affect vertical alignment and scrolling.

Practice

1. Which Bootstrap class would you add to a modal dialog to make it appear smaller than the default size?

easy

A. modal-centered

B. modal-lg

C. modal-xl

D. modal-sm

Solution

1. Step 1: Understand modal size classes

   Bootstrap provides specific classes to control modal sizes: modal-sm for small, modal-lg for large, and modal-xl for extra large modals.

2. Step 2: Identify the class for smaller modal

   The class modal-sm is used to make the modal smaller than the default size.

3. Final Answer:

   <code>modal-sm</code> -> Option D

4. Quick Check:

   Small modal = modal-sm [OK]

Hint: Small modal uses modal-sm class [OK]

Common Mistakes:

• Using modal-lg or modal-xl for small size
• Confusing modal-centered with size classes
• Not adding any size class and expecting smaller modal

2. Which of the following is the correct way to center a Bootstrap modal vertically on the screen?

easy

A. Add modal-dialog-centered to the modal-dialog div

B. Add centered-modal to the modal div

C. Add modal-center to the modal-content div

D. Add modal-vertical to the modal-dialog div

Solution

1. Step 1: Identify the correct class for vertical centering

   Bootstrap uses the class modal-dialog-centered on the modal-dialog element to vertically center the modal.

2. Step 2: Verify the element to apply the class

   The class must be added to the modal-dialog div, not modal or modal-content.

3. Final Answer:

   Add modal-dialog-centered to the modal-dialog div -> Option A

4. Quick Check:

   Vertical center = modal-dialog-centered on modal-dialog [OK]

Hint: Use modal-dialog-centered on modal-dialog div [OK]

Common Mistakes:

• Adding centering class to wrong modal element
• Using non-existent classes like modal-center
• Confusing modal-dialog-centered with modal size classes

3. What will be the visual size of the modal dialog in this code snippet?

<div class="modal-dialog modal-xl">
  <div class="modal-content">
    <!-- Modal body -->
  </div>
</div>

medium

A. Small modal dialog

B. Default modal dialog size

C. Extra large modal dialog

D. Centered modal dialog

Solution

1. Step 1: Identify the size class used

   The class modal-xl is applied to the modal-dialog div, which sets the modal to extra large size.

2. Step 2: Understand the effect of modal-xl

   This class makes the modal wider than default and large sizes, so the modal will appear extra large on the screen.

3. Final Answer:

   Extra large modal dialog -> Option C

4. Quick Check:

   modal-xl = extra large modal [OK]

Hint: modal-xl class means extra large modal [OK]

Common Mistakes:

• Confusing modal-xl with modal-lg or modal-sm
• Thinking modal-xl centers the modal
• Ignoring the class and assuming default size

4. You want to make a modal vertically centered and large sized. Which of these code snippets correctly applies both features?

A) <div class="modal-dialog modal-lg modal-dialog-centered">
B) <div class="modal-dialog modal-centered modal-lg">
C) <div class="modal-dialog modal-lg-centered">
D) <div class="modal-dialog modal-lg center-dialog">

medium

A. A

B. B

C. C

D. D

Solution

1. Step 1: Check correct Bootstrap classes for size and centering

   The correct classes are modal-lg for large size and modal-dialog-centered for vertical centering.

2. Step 2: Verify the class names and order

   A uses both classes correctly on the modal-dialog div. Other options use incorrect or non-existent classes.

3. Final Answer:

   Option A -> Option A

4. Quick Check:

   modal-lg + modal-dialog-centered = A [OK]

Hint: Combine modal-lg and modal-dialog-centered on modal-dialog [OK]

Common Mistakes:

• Using wrong class names like modal-centered or modal-lg-centered
• Placing classes on wrong elements
• Missing one of the required classes

5. You want to create a responsive modal that is small on mobile, large on tablets, and extra large on desktops, and also vertically centered. Which Bootstrap classes should you apply to the modal-dialog to achieve this?

hard

A. modal-dialog modal-sm modal-lg modal-xl modal-dialog-centered

B. modal-dialog modal-dialog-centered plus custom CSS media queries for sizes

C. modal-dialog modal-dialog-centered modal-sm modal-lg modal-xl

D. modal-dialog modal-dialog-centered modal-sm modal-lg modal-xl with responsive utility classes for each breakpoint

Solution

1. Step 1: Understand Bootstrap modal size classes

   Bootstrap modal size classes like modal-sm, modal-lg, and modal-xl are not responsive by themselves and cannot be combined to change size at different screen widths.

2. Step 2: Identify how to make modal responsive

   To have different modal sizes on different devices, you must use modal-dialog-centered for vertical centering and write custom CSS media queries to adjust modal width responsively.

3. Final Answer:

   modal-dialog modal-dialog-centered plus custom CSS media queries for sizes -> Option B

4. Quick Check:

   Responsive modal sizes require custom CSS + modal-dialog-centered [OK]

Hint: Use modal-dialog-centered plus CSS media queries for responsiveness [OK]

Common Mistakes:

• Trying to combine multiple size classes on modal-dialog
• Assuming Bootstrap size classes are responsive by default
• Not adding vertical centering class