JS. Beginner JavaScript Questions Breakdown to Crack Any Interview:

 Level         Type

Beginner                    Basics (syntax, variables, data types, operators, loops, functions)


🎯 Key JavaScript Topics You Must Prepare

📌 Basics

  • What is JavaScript?

  • Variables (var, let, const)

  • Data Types: string, number, boolean, undefined, null, object

  • Operators: arithmetic, comparison, logical

  • Conditional Statements (if, else, switch)

  • Loops: for, while, do...while

📌 Functions

  • Function Declaration & Expression

  • Arrow Functions (()=>)

  • Parameters vs Arguments

  • Return values

📌 Scope & Closures

  • Global vs Local Scope

  • Lexical Scope

  • Closure: inner function accessing outer variable

📌 Arrays & Objects

  • Array methods: push(), pop(), map(), filter(), reduce()

  • Object properties, methods, destructuring

📌 ES6+ Features

  • Template literals

  • Default parameters

  • Spread/rest operator

  • Destructuring

  • let vs const vs var

📌 DOM Manipulation

  • document.getElementById(), querySelector()

  • innerText, innerHTML, value

  • Add/Remove/Toggle Classes

📌 Events

  • Event types: click, submit, keyup, etc.

  • addEventListener()

  • Event bubbling vs capturing

📌 Asynchronous JavaScript

  • Callbacks

  • Promises

  • async / await

  • Fetch API

📌 Advanced Concepts

  • Hoisting

  • this keyword

  • Event loop

  • Prototypes & Inheritance

  • bind(), call(), apply()

🚀 Bonus Tips

🔹 Real-World Mini Projects to Practice:

  • To-Do List App (DOM & Events)

  • Calculator (Functions & Event Handling)

  • API Search (Fetch + DOM)

  • Form Validation (Regex + DOM)

🔹 Practice on Platforms:





1. What is JavaScript?
➤ JavaScript is a scripting language used to create dynamic and interactive content on websites.


2. Difference between var, let, and const?
➤ var is function-scoped, let and const are block-scoped; const can’t be reassigned.

3.What are data types in JavaScript?
➤ Primitive: string, number, boolean, null, undefined, symbol, bigint.
➤ Non-primitive: objects, arrays, functions.

4.How do you write a function in JavaScript?
Ans.

function greet(name) {
    return "Hello "+name;
}


5. What is the difference between == and ===?
➤ == checks value only (type conversion happens), === checks value and type (strict equality).

6. What is an array in JavaScript?
➤ An array is a list-like object used to store multiple values.

7. What is a loop? Name types of loops.
➤ Loops are used to run code repeatedly. Types: for, while, do...while.

8. What are template literals?
➤ Strings using backticks: `Hello, ${name}` for embedding expressions.

9.What are arrow functions?
➤ A shorter syntax to write functions:
const greet = name => `Hi ${name}`;


10. How do you declare a variable in JavaScript?
➤ let age = 25;, const name = "John";









































































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