First Bootstrap page - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ rendering

intermediate

What will this Bootstrap page display?

Look at the HTML code below. What will you see in the browser when this page loads?

Bootsrap

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Bootstrap Test</title>
  <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/css/bootstrap.min.css" rel="stylesheet">
</head>
<body>
  <div class="container">
    <h1 class="text-primary">Welcome to Bootstrap!</h1>
    <p class="lead">This is your first Bootstrap page.</p>
  </div>
</body>
</html>

A A red heading and a normal paragraph with no special styling.

B A blue heading saying 'Welcome to Bootstrap!' and a slightly larger paragraph below it.

C A plain black heading and paragraph with no Bootstrap styles applied.

D An error message because Bootstrap CSS is missing.

💡 Hint

Look at the class names and the Bootstrap CSS link in the head.

The class 'text-primary' makes the heading blue using Bootstrap's primary color. The 'lead' class makes the paragraph text larger and lighter. The Bootstrap CSS is loaded from the CDN, so styles apply correctly.

❓ selector

intermediate

Which Bootstrap class adds spacing around an element?

You want to add margin space around a

using Bootstrap. Which class should you use?

A m-3

B p-3

C text-center

D bg-primary

💡 Hint

Bootstrap uses 'm' for margin and 'p' for padding.

The class 'm-3' adds margin (space outside the element) on all sides. 'p-3' adds padding (space inside). 'text-center' centers text, and 'bg-primary' changes background color.

❓ layout

advanced

How does Bootstrap's grid system layout behave on small screens?

Given this Bootstrap grid code, how will the columns appear on a small screen (less than 576px wide)?

Column 1

Column 2

Column 3

A All three columns stack vertically, each taking full width.

B All three columns appear side by side in one row, each taking one-third width.

C Only the first two columns appear side by side; the third stacks below.

D Columns disappear because 'col-sm-4' only works on medium screens.

💡 Hint

Bootstrap grid classes with 'sm' apply from small screens and up.

The 'col-sm-4' class applies starting at small screens (≥576px). Below 576px, columns stack vertically and take full width by default.

❓ accessibility

advanced

Which attribute improves accessibility for a Bootstrap modal?

You have a Bootstrap modal dialog. Which attribute should you add to the modal's main

to help screen readers?

A tabindex="-1"

B data-toggle="modal"

C role="button"

D aria-labelledby="modalTitle"

💡 Hint

Screen readers need to know the modal's title for context.

The 'aria-labelledby' attribute points to the element that labels the modal, helping screen readers announce the modal's purpose. 'data-toggle' is for JavaScript behavior, 'role="button"' is for buttons, and 'tabindex="-1"' manages focus but doesn't label.

🧠 Conceptual

expert

What is the main benefit of using Bootstrap's container class?

Why do Bootstrap pages often wrap content inside a

element?

A It disables scrolling on the page to keep content fixed.

B It automatically adds a background color and border to the page content.

C It centers the content and adds responsive horizontal padding to keep content aligned on all screen sizes.

D It converts all text inside to uppercase for better readability.

💡 Hint

Think about how content looks on different screen sizes.

The 'container' class centers content horizontally and adds padding on the sides. It also adjusts width responsively to keep content neat on all devices. It does not add background, disable scrolling, or change text case.

Practice

1. What is the main purpose of including Bootstrap CSS in your HTML page?

easy

A. To create backend server logic

B. To apply ready-made styles and layout to your webpage quickly

C. To make your page load faster by compressing images

D. To add interactive JavaScript features only

Solution

1. Step 1: Understand Bootstrap CSS role

   Bootstrap CSS provides pre-built styles and layout helpers to style HTML elements easily.

2. Step 2: Differentiate CSS from JS and backend

   CSS controls appearance, not backend logic or image compression, and JS adds interactivity but is separate.

3. Final Answer:

   To apply ready-made styles and layout to your webpage quickly -> Option B

4. Quick Check:

   Bootstrap CSS = ready styles [OK]

Hint: Bootstrap CSS styles your page fast, not backend or speed [OK]

Common Mistakes:

• Confusing Bootstrap CSS with JavaScript functionality
• Thinking Bootstrap compresses images
• Assuming Bootstrap handles backend logic

2. Which of the following is the correct way to include Bootstrap CSS from a CDN in your HTML <head>?

easy

A.

B.

C.

D.

Solution

1. Step 1: Identify correct HTML tag for CSS

   CSS files are included using the <link> tag with rel="stylesheet" attribute.

2. Step 2: Check the CDN URL and tag correctness

   <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/css/bootstrap.min.css"> uses <link> with correct href to Bootstrap CSS CDN, others misuse tags or attributes.

3. Final Answer:

   <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/css/bootstrap.min.css"> -> Option C

4. Quick Check:

   CSS uses <link rel="stylesheet"> [OK]

Hint: Use for CSS files [OK]

Common Mistakes:

• Using <script> tag for CSS files
• Using <style> tag with src attribute
• Wrong attribute values like rel="script"

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

<div class="container">
  <button class="btn btn-primary">Click Me</button>
</div>

medium

A. A blue styled button labeled 'Click Me' centered with some padding

B. A plain button with no special styling

C. A red button labeled 'Click Me' with no padding

D. An error because 'btn-primary' is not a valid class

Solution

1. Step 1: Understand Bootstrap container and button classes

   The 'container' class adds horizontal padding and centers content. 'btn btn-primary' styles a button with Bootstrap's primary blue color and padding.

2. Step 2: Predict visual output

   The button will appear blue with white text, some padding, and be inside a padded container.

3. Final Answer:

   A blue styled button labeled 'Click Me' centered with some padding -> Option A

4. Quick Check:

   btn-primary = blue button style [OK]

Hint: btn-primary means a blue Bootstrap button [OK]

Common Mistakes:

• Thinking btn-primary is red
• Ignoring container padding effect
• Assuming no styling without extra CSS

4. Identify the error in this Bootstrap page snippet:

<html>
<head>
  <link rel="stylesheet" href="bootstrap.min.css">
</head>
<body>
  <div class="container">
    <button class="btn btn-primary">Submit</button>
  </div>
</body>
</html>

medium

A. Container class should be 'container-fluid' instead

B. Button class 'btn-primary' is misspelled

C. Missing closing tag for <button>

D. Bootstrap CSS file path is likely incorrect or missing CDN link

Solution

1. Step 1: Check Bootstrap CSS inclusion

   The link uses 'bootstrap.min.css' without a full path or CDN, which may cause the file not to load if not locally present.

2. Step 2: Verify other elements

   Button class spelling is correct, button tag is properly closed, and 'container' is valid Bootstrap class.

3. Final Answer:

   Bootstrap CSS file path is likely incorrect or missing CDN link -> Option D

4. Quick Check:

   Missing or wrong CSS link breaks Bootstrap styles [OK]

Hint: Always use full CDN URL or correct local path for Bootstrap CSS [OK]

Common Mistakes:

• Assuming local CSS file always exists
• Confusing container and container-fluid classes
• Overlooking missing or wrong file paths

5. You want to create a simple Bootstrap page with a navigation bar and a button below it. Which of the following code snippets correctly sets up the basic Bootstrap page structure including CSS and JS from CDN?

hard

A.

Bootstrap Page

Navbar

Click Me

B.

Bootstrap

Navbar

Click

C.

Page

Nav

Press

D.

Bootstrap

Navbar

Click

Solution

1. Step 1: Check for complete Bootstrap setup

   <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1"> <title>Bootstrap Page</title> <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/css/bootstrap.min.css" rel="stylesheet"> </head> <body> <nav class="navbar navbar-expand-lg navbar-light bg-light"> <div class="container-fluid"> <a class="navbar-brand" href="#">Navbar</a> </div> </nav> <div class="container mt-3"> <button class="btn btn-success">Click Me</button> </div> <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/js/bootstrap.bundle.min.js"></script> </body> </html> includes DOCTYPE, language, charset, viewport meta, Bootstrap CSS and JS from CDN, and uses proper navbar and button classes.

2. Step 2: Compare other options for missing parts

   <html> <head> <title>Bootstrap</title> <link rel="stylesheet" href="bootstrap.css"> </head> <body> <nav class="navbar"> <a href="#">Navbar</a> </nav> <button class="btn btn-primary">Click</button> </body> </html> lacks DOCTYPE, viewport meta, and uses local CSS without JS. <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Page</title> <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/js/bootstrap.min.js"></script> </head> <body> <nav class="navbar navbar-dark bg-dark"> <a class="navbar-brand" href="#">Nav</a> </nav> <button class="btn btn-danger">Press</button> </body> </html> misses viewport meta and uses only JS without CSS. <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1"> <title>Bootstrap</title> <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/css/bootstrap.min.css"> </head> <body> <nav class="navbar navbar-light bg-light"> <a class="navbar-brand" href="#">Navbar</a> </nav> <button class="btn btn-warning">Click</button> </body> </html> misses Bootstrap JS and container for spacing.

3. Final Answer:

   Option A has the correct full Bootstrap page structure with CSS and JS from CDN -> Option A

4. Quick Check:

   Complete Bootstrap page = <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1"> <title>Bootstrap Page</title> <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/css/bootstrap.min.css" rel="stylesheet"> </head> <body> <nav class="navbar navbar-expand-lg navbar-light bg-light"> <div class="container-fluid"> <a class="navbar-brand" href="#">Navbar</a> </div> </nav> <div class="container mt-3"> <button class="btn btn-success">Click Me</button> </div> <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/js/bootstrap.bundle.min.js"></script> </body> </html> [OK]

Hint: Full Bootstrap page needs DOCTYPE, meta, CSS and JS CDN links [OK]

Common Mistakes:

• Omitting viewport meta tag
• Not including Bootstrap JS bundle
• Using local files without confirming availability