Specialization Track

JavaScript & Web Technologies Interview Questions & Answers

Closures, event loop, promises, async/await, DOM, React patterns, and modern ES6+.

Intermediate 428 views

Explain the JavaScript Event Loop, Call Stack, Microtask, and Macrotask Queues

JavaScript is a single-threaded runtime with a non-blocking, asynchronous event-driven I/O model. It uses the Event Loop to orchestrate execution between synchronous operations and asynchronous callba...

Verified Model Solution View Full Answer

Easy 6 views

How do let, const, and var differ in scope and reassignment?

let and const are block-scoped, while var is function-scoped or script-global depending on context. const prevents reassigning the binding, but it does not make a referenced object immutable. let perm...

Verified Model Solution View Full Answer

Medium 6 views

How do event bubbling and delegation help with a dynamic list of buttons?

Many events propagate from the target through ancestor elements. Delegation attaches a listener to a stable ancestor and identifies the relevant descendant, avoiding one listener per dynamically creat...

Verified Model Solution View Full Answer

Easy 5 views

What is a closure? Show a practical example.

A closure is a function together with access to its surrounding lexical environment. The function can use those variables even after the outer function has returned. A counter factory can create indep...

Verified Model Solution View Full Answer

Medium 5 views

What is the output of synchronous code, a resolved promise, and setTimeout with zero delay?

The synchronous statements run first. A promise reaction runs as a microtask after the current task completes, before the next eligible timer task. A zero-delay timer does not mean immediate execution...

Verified Model Solution View Full Answer

Medium 5 views

How should fetch code handle HTTP errors and malformed JSON?

fetch usually rejects for network failures, but it resolves for HTTP responses such as 404 or 500. Check response.ok or an expected status before treating the response as successful. JSON parsing can ...

Verified Model Solution View Full Answer

Medium 5 views

A live-search page sometimes shows results for an older query. How would you fix it?

Responses can arrive out of order, so the last response received may belong to an earlier query. Track a monotonically increasing request identifier and update the UI only when it matches the current ...

Verified Model Solution View Full Answer

Other Categories

Software Engineering & OOP 8 AI & Machine Learning 12 Data Structures & Algorithms 11 IT Staffing & Recruitment 9 JavaScript & Web Technologies 7 Cybersecurity & InfoSec 7 Python Programming 13 Data Science & Analytics 6 Java 18 Full Stack Web Development 13 SQL & Relational Databases 12 Computer Networks & OS 13 Cloud & DevOps Engineering 6 HR Interview 14 Data Science & Machine Learning 6 General 21 .NET 12 C++ and C 18 Networking 11 Windows 11 Unix / Linux 17 Visual Basic 8 Hardware 13 Database 9 Testing 19 Web Development 12 x86 13 Designing 6 Programming 2 Marketing 1 BPO 3 Customer Support 0 Technical Support 1 CCNA 3 Aptitude 1 FAQ 19 Engineering 3 Manufacturing 2 Backend 0

Practice Placement MCQs

Test your aptitude, quantitative reasoning, and core programming skills under timed conditions.

Start Placement Test