The IIT Madras BS Modern Application Development II (MAD 2) Quiz 2 paper sat on 12 Apr 2026, in the January 2026 term: 15 questions for 47 marks in 120 minutes. Every question is below with its answer. Take it as a timed mock test to be marked, or read it through first.
You are building a login feature for a web application. The frontend sends the user’s email and password to the backend API. The backend validates credentials against a database. Which security issues exist in the code given below?
Frontend: script.js
Backend: app.py
The SQL query is vulnerable to SQL injection attacks
Passwords are stored and compared in plain text
No authentication token (session/JWT) mechanism is implemented
All of these.
Correct answer
All of these.
Consider the following Vue.js code.
What will be printed on the console first?
0
done
1
Error
Correct answer
1
Consider the following Vue.js application with two different route scenarios and a component that uses reactive data binding:
Scenario: An e-commerce application where: Product list component displays products filtered by category• Category changes through router parameters: /products/:category• When a user navigates from /products/electronics to /products/books, the product list should update • Component Code:
If the developer changed the template to use displayedProducts instead of filteredProducts, What would be the most likely issue?
Performance would improve because computed properties are slower than data
The initial page load would show an empty list, and only after navigation would data appear correctly
There would be no difference because both will update at the same time
The application would crash because displayedProducts is reactive
Correct answer
The initial page load would show an empty list, and only after navigation would data appear correctly
Consider the following JavaScript code:
What will be printed to the console?
12
10
5
3
Correct answer
3
Match the following web dev concept given below:
Which of the following options correctly matches Concept / Issue and Description?
A→2, B→4, C→1, D→3
A→1, B→2, C→3, D→4
A→2, B→1, C→4, D→3
A→4, B→2, C→1, D→3
Correct answer
A→2, B→4, C→1, D→3
Consider the following Vuex store setup for a user management system:
Suppose the following mutation is committed:store.commit("updateUserStatus", { userId: 2, status: "active" });. Which of the following statements is TRUE after this mutation is executed?
The mutation will not affect any getter output
Correct answer
In Vue 2 (CDN), which of the following correctly describes the timing of the beforeDestroy and destroyed lifecycle hooks?
beforeDestroy runs after the component has been removed from the DOM, while destroyed runs before destruction.
beforeDestroy runs just before the component is torn down and removed from the DOM, while destroyed runs after the component is fully destroyed.
beforeDestroy runs when the component is first mounted, while destroyed runs before the component is removed.
both hooks run only after the component is destroyed.
Correct answer
beforeDestroy runs just before the component is torn down and removed from the DOM, while destroyed runs after the component is fully destroyed.
Consider the following HTML:
And JavaScript code:
What are the values of id and action respectively?
id = 42 (number), action = "delete" (string)
id = 42 (string), action = "delete" (string)
id = undefined, action = undefined
id = 42 (number), action = undefined
Correct answer
id = 42 (string), action = "delete" (string)
Which of the following statements best describes a permalink?
A temporary URL generated for a single browsing session
A stable URL that uniquely identifies a specific resource and is not expected to change
A human-readable URL used only for navigation menus
A URL that depends on the user’s login session or device
Correct answer
A stable URL that uniquely identifies a specific resource and is not expected to change
Consider the following code snippet running in a browser.
What will be the output on the console?
Shield 99 99 42
Shield 10 99 42
Sword 99 99 42
Shield 99 42 42
Correct answer
Shield 99 99 42
Consider the following code snippet running on a browser. What is the output on the console?
42 42 42
42 undefined undefined
42 undefined 42
undefined undefined undefined
Correct answer
42 undefined undefined
Consider the following markup index.html and JavaScript app.js for a Vue application.
app.js:
index.html:
Suppose the application is running on http://localhost:8080, and the user visit the URL “http://localhost:8080/\#/player/rohit/t20”. What will be rendered by the browser?
Name: Rohit Oneday Runs: 10000
Test Runs: 5000
Name: Rohit Test Runs: 5000
Oneday Runs: 10000
Correct answer
Test Runs: 5000
Consider the following html index.html and JavaScript app.js for a Vue application:
File : index.html
File : app.js
Suppose the application is running on http://localhost:8080, and the user visits the URL http://localhost:8080/\#/b. What will be rendered by the browser?
Shivamogga
South Goa
Rewa
Satara
Correct answer
Rewa
Consider a scenario involving localStorage, Promise chains, and Vue lifecycle hooks:
Scenario: A user authentication system where: On app initialization, the app checks localStorage for a stored user token• If a token exists, it validates the token asynchronously (via a Promise)• Based on validation, different UI components are rendered• The user navigates between different views• Code in mounted() hook:
Which of the following statements is/are CORRECT about this implementation?
If the page is refreshed while the Promise is pending, the token will be lost because localStorage is cleared on refresh
If token validation fails, the token is removed from storage, preventing automatic login on future page loads
The isAuthenticated flag might be false even though a storedToken exists, until the Promise validation completes
sessionStorage should be used instead of localStorage because user tokens should not persist across browser sessions
If the user navigates to a different route while validation is pending, the Promise will still complete and update the user data
Correct answers
If token validation fails, the token is removed from storage, preventing automatic login on future page loads
The isAuthenticated flag might be false even though a storedToken exists, until the Promise validation completes
If the user navigates to a different route while validation is pending, the Promise will still complete and update the user data
Consider the following HTML index.html and JavaScript app.js for a Vue application:
File: index.html
File: app.js
Which of the following statements is/are TRUE?
On initial page load, neither “Hello” nor “World” is visible in the browser.
On initial page load, the element using v-show exists in the DOM but is hidden.
After clicking the Toggle button once, both “Hello” and “World” become visible.
The v-if directive hides elements using CSS.
The v-show directive removes elements from the DOM when the condition is false.
Correct answers
On initial page load, neither “Hello” nor “World” is visible in the browser.
On initial page load, the element using v-show exists in the DOM but is hidden.
After clicking the Toggle button once, both “Hello” and “World” become visible.
