JS Space

What do you understand about JavaScript?

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JavaScript is a popular web scripting language and is used for client-side and server-side development. The JavaScript code can be inserted into HTML pages that can be understood and executed by web browsers while also supporting object-oriented programming abilities.

What is th e various data types in JavaScript?

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JavaScript has 7 main data types to provide basic functionality needed for a web application.

Boolean - for true and false values;
Null - for empty or unknown values;
Undefined - for variables that are only declared and not defined or initialized;
Number - for integer and floating-points values;
String - for characters and alphanumeric values;
Object - for collections or complex values;
Symbols - for unique identifiers or objects;

What are the features of JavaScript?

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Lightweight, interpreted programming language;
Cross-platform compatible;
Open-source;
Object-oriented;
Integration with other backend as well as frontend technologies;
Used especially for the development of network-based applications;

What are the advantages of JavaScript?

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Enhanced interaction - JavaScript adds interaction to otherwise static web pages and makes them react to users' inputs
Quick feedback -There is no need for a web page to reload when running JavaScript
Rich User Interface - JavaScript helps in making the UI of web applications look and feel much better
Frameworks - JavaScript has countless frameworks and libraries that are extensively used for developing web applications and games of all kinds

How do you create an object in JavaScript?

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Since JavaScript is essentially an object- oriented scripting language, it supports the usage of objects while developing web applications

How do you create an array in JavaScript?

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Here is a very simple way of creating arrays in JavaScript using the array literal:

What are some of the built-in methods in JavaScript?

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JavaScript has many built-in methods to provide functionality needed for a web app
Some of them are mentioned in this table

Method	Definition
Date()	Returns the present date and time
Concat()	Joins two strings and returns the new string
Push()	Adds an item to an array
Pop()	Removes and also returns the last element of an array
Round()	Rounds of the value to the nearest integer and returns it
Length()	Returns the length of a string

What are the scopes of a variable in JavaScript?

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The scope of a variable basically implies where the variable has been declared or defined in a JavaScript program

Global Scope - Global variables, having global scope are available everywhere in a JavaScript code
Local Scope - Local variables are accessible only within a function in which they are defined

What is 'this' keyword in JavaScript?

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The 'this' keyword in JavaScript refers to the currently calling object. It is commonly used in constructors to assign values to object properties.

JavaScript Interview Questions and Answers

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