Global Variables in Programming

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Questions and Answers

What is the purpose of JavaScript comments?

To execute a specific block of code
To make the code easy to read and understand (correct)
To declare a variable
To make the code more difficult to read

What is the syntax for a single-line comment in JavaScript?

" line to be commented "
** line to be commented **
// line to be commented (correct)

What is the purpose of the prompt() function in JavaScript?

To display a message to the user (correct)
To execute a specific block of code
To perform arithmetic operations
To declare a variable

What is the result of a comparison between values in JavaScript?

A boolean value (D) Signup and view all the answers

What is the operator used to check if two values are equal and are of the same type?

=== (B) Signup and view all the answers

What is the purpose of the default message in the prompt() function?

To provide a default value for user input (C) Signup and view all the answers

What is the syntax for a multiline comment in JavaScript?

/* comment */ (B) Signup and view all the answers

What is the purpose of the assignment operators in JavaScript?

To assign a value to a variable (D) Signup and view all the answers

What is the main advantage of using global variables in JavaScript?

They can be used to store data in one place and access it from anywhere in the code. (D) Signup and view all the answers

Which of the following keywords can be used to declare a variable that can change its data type?

let (B), var (C) Signup and view all the answers

What is the purpose of the prompt() function in JavaScript?

To display a dialog with an optional message and take user input. (C) Signup and view all the answers

What will happen if a variable is declared with the let keyword but not initialized?

It will show undefined. (C) Signup and view all the answers

What is the scope of a variable declared with the let keyword?

Block scope. (B) Signup and view all the answers

What is the difference between variables declared with the var and let keywords?

Variables declared with var have a global scope, while variables declared with let have a block scope. (C) Signup and view all the answers

What is the default value of a variable declared with the let keyword but not initialized?

Undefined. (C) Signup and view all the answers

What is the purpose of using global variables in JavaScript?

To store data in one place and access it from anywhere in the code. (C) Signup and view all the answers

What is JavaScript?

A weakly typed language (C) Signup and view all the answers

What is the extension of a JavaScript file?

.js (D) Signup and view all the answers

Which method is used to display an alert box with a specified message?

window.alert() (B) Signup and view all the answers

What is the purpose of the document.write() method?

To print output to the browser's webpage (C) Signup and view all the answers

What is the purpose of the innerHTML property?

To set an inner HTML element (C) Signup and view all the answers

What is the purpose of the console.log() method?

To write a message to the console (D) Signup and view all the answers

How can JavaScript be used?

For both Client-Side and Server-side developments (B) Signup and view all the answers

Where can JavaScript codes be placed in HTML?

Between the script tags (D) Signup and view all the answers

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Study Notes

Global Variables

Global variables are declared outside of function declarations and can be accessed from anywhere in the code.
They allow storing data in one place and accessing it from anywhere in the code.

Variable Declaration Keywords

let keyword: can change the data type of a variable, and the value declared inside a scope cannot be used outside.
var keyword: can change the data type of a variable, and the value declared inside a scope cannot be used outside.
const keyword: cannot change the data type of a variable, and the value declared inside a scope cannot be used outside.

Input in JavaScript

The prompt() function is used to take user input in JavaScript, displaying a dialog with an optional message.
The prompt() function is part of the window object.

Introduction to JavaScript

JavaScript is a weakly typed language (dynamically typed).
JavaScript can be used for client-side and server-side developments.
JavaScript is both an imperative and declarative type of language.
JavaScript contains a standard library of objects, such as Array, Date, and Math, and a core set of language elements like operators, control structures, and statements.