Bootstrap Interview Questions and Answers: Ace Your Next Interview

Prepare for your next Bootstrap interview with this comprehensive guide. Learn common Bootstrap interview questions and answers, covering key concepts, components, and best practices for front-end web development.

Bootstrap Interview Questions and Answers

Last Updated: 03 Jul, 2024

Bootstrap is a popular open-source framework for creating responsive, mobile-first websites. It provides HTML, CSS, and JavaScript components to streamline web development.

Common Bootstrap Interview Questions

Q1. What is Bootstrap?

Bootstrap is a free and open-source framework for creating responsive websites and web applications. It supports features like forms, buttons, tables, navigation bars, and carousels, making web development faster and easier.

Q2. What are the features of Bootstrap?

• Open-source and free
• Compatible with all major browsers
• Responsive design support
• Quick and simple to use

Q3. How many different layouts does Bootstrap have?

Bootstrap offers two primary layouts:

• Fluid Layout: Spans 100% of the screen width.
• Fixed Layout: Uses a standard width display.

Q4. Give an example of a basic grid structure in Bootstrap.

<div class="container">
    <div class="row">
        <div class="col-lg">Column-1</div>
        <div class="col-lg">Column-2</div>
    </div>
</div>

Q5. What is a Bootstrap progress bar?

A progress bar visually represents the progress of a task. Bootstrap provides predefined classes such as .bg-success, .bg-info, and .bg-warning for customization.

Q6. Why is Bootstrap preferred for web development?

Bootstrap simplifies web development by offering cross-browser compatibility, responsive design features, and an extensive collection of ready-to-use components, reducing the need for custom CSS and JavaScript.

Q7. What is the difference between Bootstrap and Foundation?

Q8. What are collapsing elements in Bootstrap?

Collapsing elements show or hide data when clicked or hovered over. Bootstrap provides predefined classes for implementing collapsing elements effortlessly.

Q9. What lists does Bootstrap support?

• Unordered Lists: Uses bullets.
• Ordered Lists: Uses numerical markers.
• Definition Lists: Items paired with descriptions.

Q11. Explain media objects in Bootstrap.

Media objects like images and videos can be aligned using classes such as .media and .media-body. They help create repetitive and complex content components.

Q12. Why is a jumbotron used in Bootstrap?

A jumbotron highlights important text by placing it in a large, noticeable grey box. To use, apply the .jumbotron class to a <div> element.

Q13. What is the carousel plugin used for?

The carousel plugin creates image or text slideshows. It is widely used for implementing sliders in web applications.

Q14. How can you make responsive images?

Add the class .img-responsive to the <img> tag to ensure images scale properly within their containers.

Q15. How can you create a navbar in Bootstrap?

A responsive navigation bar can be created using the navbar class, e.g., <nav class="navbar navbar-default">. Additional features include drop-down menus and search boxes.

Q16. What is a Bootstrap container?

Bootstrap containers are fundamental layout components used to wrap content. Use the .container class for aligning content to the viewport or device.

Q17. What is the Bootstrap Grid System?

Bootstrap's Grid System divides the page into 12 columns. Columns can be used individually or merged for wider layouts.

Q18. What are the key components of Bootstrap?

• CSS for styling
• Scaffolding for basic frameworks
• JavaScript plugins
• Customizable components

Q19. What are Glyphicons?

Glyphicons are icon fonts included in Bootstrap. Add them to your code with the following syntax:

<span class="glyphicon glyphicon-search"></span>

Q20. How do you create forms using Bootstrap?

To create forms:

1. Include Bootstrap CDN links.
2. Add form elements like input fields within a <form> tag using Bootstrap's predefined classes.

Q21. What do you mean by Bootstrap well?

A Bootstrap well is a container with rounded borders and padding, used to highlight specific content. The .well class applies a gray background, rounded borders, and padding. You can customize its appearance using CSS.

Q22. What are the input groups in Bootstrap?

Input groups extend form controls with text or buttons on either side of inputs. Key classes:

• .input-group-prepend: Adds content before the input.
• .input-group-append: Adds content after the input.
• .input-group-text: Styles the content inside the group.

Q23. What is Bootstrap breadcrumb?

Breadcrumbs indicate the current page’s location within a navigational hierarchy.

<ol class="breadcrumb">
  <li class="breadcrumb-item">Home</li>
</ol>

Q24. What are Bootstrap alerts and how will you create them?

Bootstrap alerts provide feedback messages. Create alerts using the .alert class and contextual classes like .alert-success or .alert-danger. Optionally, add a close button.

Q25. Steps to create a progress bar in Bootstrap:

1. Use .progress inside a <div>.
2. Include another <div> with .progress-bar.
3. Set the progress percentage using the style attribute (e.g., style="width: 50%;").

Q26. Difference between Bootstrap 4 and Bootstrap 5:

• Bootstrap 5 includes an additional breakpoint (xxl).
• jQuery is removed in Bootstrap 5; it uses vanilla JavaScript.
• Bootstrap 5 allows utility customization.
• SVG icons are available in Bootstrap 5.
• Jumbotron is deprecated in Bootstrap 5.

Q27. Tooltip vs. Popover:

Tooltip: Appears when hovering over an element.

Popover: Appears when clicking an element and can contain more information.

Default positions: Tooltip (top), Popover (right).

Q28. What is column ordering in Bootstrap?

Column ordering changes the grid layout order based on screen size, making designs responsive.

Q29. What Are Bootstrap Media Queries?

Bootstrap media queries allow layouts to adjust based on screen size. Common breakpoints include xs, sm, md, lg, xl, and xxl.

Q30. What is Normalize in Bootstrap?

Normalize.css ensures cross-browser uniformity by providing consistent default styles for HTML elements.

Q31. Two methods for displaying code in Bootstrap:

• Inline: Use the <code> tag.
• Block: Use the <pre> tag for multi-line code.

Q32. What are Bootstrap panels?

Panels are rectangular containers for adding content. Add a heading with the .panel-heading class.

Q33. Purpose of the Scrollspy plugin:

Scrollspy updates navigation links based on the scroll position. It can be horizontal or vertical.

Q34. Why use the affix plugin in Bootstrap?

The affix plugin attaches elements to a specific position on the page and toggles pinning based on scroll position.

Q35. Button group and its class:

Button groups stack buttons inline. Use .btn-group to group buttons together.

Q36. Why use Bootstrap?

• Speeds up development.
• Responsive and platform-independent.
• Ideal for mobile web apps.

Q37. Steps to create thumbnails:

1. Include Bootstrap and jQuery CDNs.
2. Add <div> with the class row.
3. Use .col-sm-6 and .col-md-3 for responsive sections.
4. Add <a class="thumbnail"> for images.

Q38. What is a Bootstrap card?

A card is a flexible container for content like headers, body, and footers. Example:

<div class="card">
  <div class="card-header">Header</div>
  <div class="card-body">Body</div>
  <div class="card-footer">Footer</div>
</div>

Q39. Types of Bootstrap spinners:

• Border spinner: Use .spinner-border.
• Growing spinner: Use .spinner-grow.

Q40. What is pagination in Bootstrap?

Pagination enables navigation between pages. Key classes:

• .pagination: Enables pagination.
• .disabled and .active: For non-clickable and active links.
• .pagination-lg and .pagination-sm: For different sizes.

Q41. Bootstrap Table and Various Classes

Bootstrap offers a range of classes to style tables effectively. These classes can help customize the table appearance, such as alternating row colors, borders, hover effects, and responsiveness.

Key Table Classes in Bootstrap:

Q42. HTML Code to Create a Basic Toast

A toast is a lightweight notification box that appears for a few seconds to alert users about actions, such as form submissions or button clicks.

<div class="toast">
    <div class="toast-header">
        <strong>Notification</strong>
        <small>2 seconds ago</small>
    </div>
    <div class="toast-body">
        Action completed successfully!
    </div>
</div>

Q43. Badges and Making Them Rounded

Badges are simple components used to display numbers or indicators, such as unread message counts. To make badges more rounded, use the .badge-pill class.

<span class="badge badge-pill badge-primary">5 New Messages</span>

Q44. Steps to Create an Animated Progress Bar

Follow these steps to create an animated progress bar in Bootstrap:

1. Include the Bootstrap and jQuery CDNs in your HTML's <head>.
2. Use a <div> with the .progress and .progress-striped classes, along with the .active class for animations.
3. Specify the progress bar's width using inline CSS.
4. Add jQuery to animate the progress bar.

<div class="progress">
    <div class="progress-bar progress-bar-striped bg-info" style="width: 50%">
        50% Complete
    </div>
</div>

Q45. Modal in Bootstrap

A modal is a popup window displayed over the current page. It closes automatically when clicking outside the modal or using the close button.

Note: Nested modals are not supported as they can harm the user experience.

<button type="button" class="btn btn-primary" data-bs-toggle="modal" data-bs-target="#exampleModal">
    Open Modal
</button>

<div class="modal fade" id="exampleModal" tabindex="-1" aria-labelledby="exampleModalLabel" aria-hidden="true">
    <div class="modal-dialog">
        <div class="modal-content">
            <div class="modal-header">
                <h5 class="modal-title" id="exampleModalLabel">Modal Title</h5>
                <button type="button" class="btn-close" data-bs-dismiss="modal" aria-label="Close"></button>
            </div>
            <div class="modal-body">
                Modal content goes here.
            </div>
            <div class="modal-footer">
                <button type="button" class="btn btn-secondary" data-bs-dismiss="modal">Close</button>
            </div>
        </div>
    </div>
</div>

Q46. Output of Progress Bars

The following code combines multiple progress bars into a single bar with total progress equal to 100%.

<div class="progress">
    <div class="progress-bar bg-success" style="width: 65%">Completed</div>
    <div class="progress-bar bg-warning" style="width: 20%">In Progress</div>
    <div class="progress-bar bg-danger" style="width: 15%">Failed</div>
</div>

Q47. Explain what is list group in Bootstrap and what is the use of it?

A list group is used to organize content into a series. It supports flexible content customization.

<ul class="list-group">
    <li class="list-group-item">Item 1</li>
    <li class="list-group-item">Item 2</li>
    <li class="list-group-item">Item 3</li>
</ul>

Q48. Explain how to use the Dropdown plugin in Bootstrap.

To create a dropdown in Bootstrap:

• Wrap items in a .dropdown class.
• Use .dropdown-toggle for toggling functionality.
• Apply .dropdown-menu and .dropdown-item to define menu items.

Q49. Define lead body copy in Bootstrap.

Lead body copy highlights a paragraph, making it larger with increased line height. Use the .lead class for this effect.

<p class="lead">This is an important message displayed prominently.</p>

Q50. Name some alternatives to Bootstrap.

Here are some alternatives to Bootstrap: