JavaScript Programming

1. What is a Promise in JavaScript? a) A function that executes asynchronously b) A callback function c) An object representing the eventual completion or failure of an asynchronous operation d) A way to handle events Click to View Answer and Explanation Answer: c) An object representing the eventual completion or failure of an asynchronous […]

1. What is the purpose of error handling in JavaScript? a) To debug the code b) To prevent the program from crashing c) To identify syntax errors d) To log errors to the console Click to View Answer and Explanation Answer: b) To prevent the program from crashing Explanation: Error handling in JavaScript is used

1. What are JavaScript modules? a) Pre-built JavaScript libraries b) JavaScript files that export and import functionality c) Functions within JavaScript d) HTML elements linked to JavaScript Click to View Answer and Explanation Answer: b) JavaScript files that export and import functionality Explanation: JavaScript modules are files that can export parts of their code (like

1. What is a class in JavaScript? a) A blueprint for creating objects b) A special type of function c) A method used for object inheritance d) A constant variable type Click to View Answer and Explanation Answer: a) A blueprint for creating objects Explanation: In JavaScript, a class is a blueprint for creating objects

1. What is an arrow function in JavaScript? a) A function that points to another function b) A shorter syntax for writing function expressions c) A function that can only be used as a callback d) A function that automatically binds to its parent object Click to View Answer and Explanation Answer: b) A shorter

1. What is hoisting in JavaScript? a) Raising all variables to the top of their function scope b) Moving function declarations to the top of the script c) Lifting up all variable and function declarations to the top of their containing scope d) Sorting variables alphabetically Click to View Answer and Explanation Answer: c) Lifting

1. What is global scope in JavaScript? a) A scope limited to a function b) A scope within a block of code c) A scope where variables are accessible from anywhere in the code d) A scope only within loops Click to View Answer and Explanation Answer: c) A scope where variables are accessible from

1. What does DOM stand for in JavaScript? a) Document Object Model b) Display Object Management c) Data Object Model d) Document Orientation Model Click to View Answer and Explanation Answer: a) Document Object Model Explanation: DOM stands for Document Object Model, which is a programming interface for web documents. It represents the page so

1. What is a regular expression in JavaScript? a) A method for error checking b) A sequence of characters forming a search pattern c) A way to write loops d) A syntax for creating arrays Click to View Answer and Explanation Answer: b) A sequence of characters forming a search pattern Explanation: In JavaScript, a

1. What is a Map in JavaScript? a) A function to map one value to another b) A collection of elements indexed by a key c) A data structure for storing geographical data d) A method to iterate over arrays Click to View Answer and Explanation Answer: b) A collection of elements indexed by a

1. What is a Set in JavaScript? a) A collection of unique values b) A collection of key-value pairs c) A type of function d) A type of loop Click to View Answer and Explanation Answer: a) A collection of unique values Explanation: In JavaScript, a Set is an object that allows you to store

1. What is the main purpose of a while loop in JavaScript? a) To iterate over the properties of an object b) To execute a block of code as long as a specified condition is true c) To execute a block of code a fixed number of times d) To handle exceptions Click to View

1. What is the purpose of the switch statement in JavaScript? a) To declare variables conditionally b) To execute a block of code among many alternatives c) To loop through a block of code d) To check for boolean conditions Click to View Answer and Explanation Answer: b) To execute a block of code among

1. What is the basic syntax of an if statement in JavaScript? a) if (condition) {statements} b) if condition {statements} c) if {condition, statements} d) if [condition] {statements} Click to View Answer and Explanation Answer: a) if (condition) {statements} Explanation: The basic syntax of an if statement in JavaScript includes the if keyword, followed by

1. What is the purpose of an array in JavaScript? a) To store multiple functions b) To organize code into reusable blocks c) To store multiple values in a single variable d) To execute a sequence of operations Click to View Answer and Explanation Answer: c) To store multiple values in a single variable Explanation:

1. What types of numbers does JavaScript support? a) Integers and floats as distinct types b) Only integers c) Only floats d) A single number type, which includes integers and floats Click to View Answer and Explanation Answer: d) A single number type, which includes integers and floats Explanation: JavaScript has only one type of

1. How are JavaScript objects typically defined? a) With the new keyword b) Using square brackets [] c) With an object literal d) Using round parentheses () Click to View Answer and Explanation Answer: c) With an object literal Explanation: JavaScript objects are commonly defined using an object literal, which is a list of name:value

1. What is the primary purpose of a function in JavaScript? a) To iterate over arrays b) To execute a block of code when invoked c) To store data d) To create HTML content Click to View Answer and Explanation Answer: b) To execute a block of code when invoked Explanation: A JavaScript function is

1. What are the basic data types in JavaScript? a) String, Number, Boolean, Object, Function b) String, Number, Boolean, Object, Undefined, Null c) String, Number, Bigint, Boolean, Undefined, Null, Symbol, Object d) String, Integer, Float, Boolean, Array Click to View Answer and Explanation Answer: c) String, Number, Bigint, Boolean, Undefined, Null, Symbol, Object Explanation: JavaScript