Vscode
Nodejs - version v18.16+
npm - version 9.6+
Extensions for vscode

initial - client side scripting language
serve side scripting language using node.js
now also - programming language

Used to create - Dynamice website and do DOM manipluation, power of WEB API's
dom - document object model - html elements - dom tree

dynamic typed language - at runtime datatype is defined
not typesafe - use typescript for typesafe

typeof keyword used to check the type of datatype for a variable

Ecmascript - standarad rules for js to run on all browsers
ES5/ES6 - modules, classes, block scoping ( let and const ), arrow functions (=>), promises (ajax, fetch), object literals ``;

to wirte js in web -> <script> tag is used

internal, external
html parses -> top to bottom
so best to write script at end of body.

->  how to write js code ?

->  datatype (Number, object, boolean, string etc)
    typeof
    variables
    var, let, const

->  scoping - function / block scope

->  operators
    control statements

->  list and Objects(key-value pairs)

->  string methods
    contactination

->  loops

->  functions
    arrow functions

->  object constructor (objectConstructor.js)

->  delete keyword (deleteOperator.js)

->  how to select DOM object
    JSON ( JSON.parse, JSON.stringify )

->  Error (try, catch, finally blocks)

->  classes (ES6)

->  object destucturing
    inheritance and prototype chain
    method overriding / overloading

->  modules
        es5( require )
        es6( import/export )
        module file extension  -> .mjs

->  maps
    sets

->  callback function

->  promises  (handle async data)
->  eventHandler
->  event propogation (determines which order object recieve events)
        event bubbling (bottom to up)/(inner to outer) - false
        event capturing (top to bottom)/(outer to inner) - true
        addEventListner("event", callback, {boolean} event propogation)

-> DOM API's
-> AJAX
        0: request not initialized
        1: server connection established
        2: request received
        3: processing request
        4: request finished and response is ready
-> Fetch