Introduction to JavaScript (staging)

Introduction to JavaScript (staging)

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1. Introduction

Writing our first code on JavaScript.

Writing our first code

Output Using Variables 1/2

Output Using Variables 2/2

2. JavaScript syntax

The syntax of the JavaScript programming language is the set of rules that defines how a JavaScript program will be written and interpreted (by both the runtime system and by human readers).

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

3. Data Types and Variables

JavaScript is dynamically typed (also called loosely typed) scripting language. That is, in javascript variables can receive different data types over time. Datatypes are basically typed of data that can be used and manipulated in a program.

Course Content

Introduction to JavaScript (staging)

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

Var 3/3

Why `var` is not used now

Due to hoisting and the global scope declaring variables with the var leads to so much confusion in the code. If we change the value of a variable at just one place intentionally the var will change that value all over the code. It will create so many unexpected results in our code.

Task

Swipe to show code editor

Hoisting is used in the following code and this code does not give any error but not a preferable approach. Your task is, using only the let keyword, to re-arrange the variables in the code and display all the variables.

Summary:

The var is an alternative to the let keyword in JavaScript.
Variables declared with var can be accessed before the declaration.
The let and const do not allow hoisting but var does.
It is not a good practice to use var instead we should use let.

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Section 3. Chapter 6

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Var 3/3

Why `var` is not used now

Due to hoisting and the global scope declaring variables with the var leads to so much confusion in the code. If we change the value of a variable at just one place intentionally the var will change that value all over the code. It will create so many unexpected results in our code.

Task

Swipe to show code editor

Hoisting is used in the following code and this code does not give any error but not a preferable approach. Your task is, using only the let keyword, to re-arrange the variables in the code and display all the variables.

Summary:

The var is an alternative to the let keyword in JavaScript.
Variables declared with var can be accessed before the declaration.
The let and const do not allow hoisting but var does.
It is not a good practice to use var instead we should use let.

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 6

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

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