Course Content

Introduction to JavaScript (staging)

1. Introduction

Writing our first code Output Using Variables 1/2 Output Using Variables 2/2

2. JavaScript syntax

JavaScript Syntax JavaScript Variables JavaScript Operators Identifiers in JavaScript Naming Identifiers Reserved keywords in JavaScript Naming Convention in JavaScript. Case Styles Variables Naming Convention Boolean Naming Convention Constant Naming Convention Function & Classes Naming Convention Multiline Strings Multiline Strings. Concatenating Commenting in JavaScript Commenting in JavaScript. Multi-line Comments

Number 1/3

Numbers in JavaScript

JavaScript provides us with double-precision floating-point number to deal with the numbers in the code. You don’t need to specifically write int or float for declaring integer or floating values, unlike other programming languages.


              12
            
let totalPlayer=10;
console.log(totalPlayer);

`+` Operator with Numbers:

+ operator is used in two ways with the number data type.

Addition: + is used for addition when both the operands are numbers, for example.


              1234
            
let firstNumber = 10;
let secondNumber = 20;
let total = firstNumber + secondNumber;
console.log(total);

Concatenation:
When one operand is a number while the other is a string, the + operator concatenate them together, for example.


              1234
            
let  company = 'Robotech ';
let  version = 10;
let  newLaunch = company + version;
console.log(newLaunch);

JavaScript NaN and Infinity:

In JavaScript, the number datatype has some exceptions which are called “Special Numeric Values”. The exceptions are:

NaN:
NaN stands for Not a Number. NaN, in JavaScript, is a keyword that is used to check whether the value or variable is not a number.
We get NaN as a result when we perform arithmetic operations other than + between a numeric value and a string value, for example.


              1234
            
let  numberOfStudent = 20;
let  greeting = 'Hello';
let  total = numberOfStudent - greeting;
console.log(total);

Infinity:
We get Infinity or -Infinity, in JavaScript, if the result of a calculation exceeds the largest possible number or the smallest possible number respectively, for example.


              12
            
console.log("2 / 0  :", 2 / 0)
console.log("-2 / 0 :", -2 / 0)

In JavaScript, you can use the isFinite() function to check whether a value or variable is Finite or not, for example.


              1234
            
let score = 123;
let status = 'Test';
console.log(isFinite(score));
console.log(isFinite(status));

Note:
If isNaN() returns true, it means that the data type is not a number.


              12
            
let name = 'Bob';
console.log(isNaN(name));

Task

Swipe to show code editor

A variable named comment with the assigned value of "hello123" has been given to you. Your task is to check and print whether the comment variable is a number or not as well as whether it is Finite or not.

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Section 3. Chapter 12

Number 1/3

Numbers in JavaScript


              12
            
let totalPlayer=10;
console.log(totalPlayer);

`+` Operator with Numbers:

+ operator is used in two ways with the number data type.

Addition: + is used for addition when both the operands are numbers, for example.


              1234
            
let firstNumber = 10;
let secondNumber = 20;
let total = firstNumber + secondNumber;
console.log(total);

Concatenation:
When one operand is a number while the other is a string, the + operator concatenate them together, for example.


              1234
            
let  company = 'Robotech ';
let  version = 10;
let  newLaunch = company + version;
console.log(newLaunch);

JavaScript NaN and Infinity:

In JavaScript, the number datatype has some exceptions which are called “Special Numeric Values”. The exceptions are:

NaN:
NaN stands for Not a Number. NaN, in JavaScript, is a keyword that is used to check whether the value or variable is not a number.
We get NaN as a result when we perform arithmetic operations other than + between a numeric value and a string value, for example.


              1234
            
let  numberOfStudent = 20;
let  greeting = 'Hello';
let  total = numberOfStudent - greeting;
console.log(total);

Infinity:
We get Infinity or -Infinity, in JavaScript, if the result of a calculation exceeds the largest possible number or the smallest possible number respectively, for example.


              12
            
console.log("2 / 0  :", 2 / 0)
console.log("-2 / 0 :", -2 / 0)

In JavaScript, you can use the isFinite() function to check whether a value or variable is Finite or not, for example.


              1234
            
let score = 123;
let status = 'Test';
console.log(isFinite(score));
console.log(isFinite(status));

Note:
If isNaN() returns true, it means that the data type is not a number.


              12
            
let name = 'Bob';
console.log(isNaN(name));

Task

Swipe to show code editor

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Everything was clear?

Thanks for your feedback!

Section 3. Chapter 12

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Introduction to JavaScript (staging)

Number 1/3

Numbers in JavaScript

+ Operator with Numbers:

JavaScript NaN and Infinity:

Number 1/3

Numbers in JavaScript

+ Operator with Numbers:

JavaScript NaN and Infinity:

`+` Operator with Numbers:

`+` Operator with Numbers: