This document provides an introduction to JavaScript. It discusses using JavaScript in the browser console or code editor, variables and data types in JavaScript like numbers, strings, Booleans, and objects. It also covers variable declaration using let, const, and var, and provides examples of creating constant objects to store product and profile information.

1. What is JavaScript?
use console in any browser or just open one of your projects and use that
the code is not permanent, we can use the up & down arrow to bring back old code
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JS is a programming language. We use it to give instructions to the computer.
Output
Input (code) Computer

2. Setting up VS Code
we'll use the chrome developer tools console to write our code
but not for long terms as afterwards we will start to use js file
like we used for css
It is a free & popular code editor by Microsoft
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3. Our 1st JS Code
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console.log(“Apna College”);
Console.log is used to log (print) a message to the console

4. Variables in JS
Variables are containers for data
memory
radius
14
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5. Variable Rules
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Variable names are case sensitive; “a” & “A” is different.
Only letters, digits, underscore( _ ) and $ is allowed. (not even space)
Only a letter, underscore( _ ) or $ should be 1st character.
Reserved words cannot be variable names.

6. let, const & var
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var : Variable can be re-declared & updated. A global scope variable.
let : Variable cannot be re-declared but can be updated. A block scope variable.
const : Variable cannot be re-declared or updated. A block scope variable.

7. Data Types in JS
Primitive Types : Number, String, Boolean, Undefined, Null, BigInt, Symbol
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8. Number
Follow
String
Boolean
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9. Let‘s Practice
Qs1. Create a const object called “product” to store information shown in the picture.
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10. Let‘s Practice
Qs2. Create a const object called “profile” to store information shown in the picture.
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