JavaScript is a versatile programming language primarily used to create dynamic and interactive features on websites.
JavaScript is a scripting language that allows you to implement complex features on web pages.
Browsers have Interpreters. It will converts JAVASCRIPT code to machine code.
Browsers have its own interpreters like

• Chrome – V8-engine
• Edge – Chakra

JavaScript- Identifiers :

var message; –> Variable (Identifier)
message = ‘Javascript’;

func sayHello() {
console.log(‘Hello’)
}

//sayHello Is the identifier for this function.

//variables , objects,functions,arrays ,classes names are identifiers in js.

SCOPE :
In JavaScript, scope refers to the context in which variables and functions are accessible. It determines the visibility and lifetime of these variables and functions within your code. There are three main types of scope in JavaScript.

Global Scope:.

• Variables declared outside any function or block have global scope.
• These variables are accessible from anywhere in the code

example :

let globalVar = "I'm global";

function test() {
  console.log(globalVar); // Accessible here
}

test();
console.log(globalVar); // Accessible here too

Function Scope

• Variables declared within a function are local to that function.
• They cannot be accessed from outside the function.

example :

function test() {
  let localVar = "I'm local";
  console.log(localVar); // Accessible here
}

test();
console.log(localVar); // Error: localVar is not defined

Block Scope:

• Introduced with ES6, variables declared with let or const within a block (e.g., inside {}) are only accessible within that block

example :

{
  let blockVar = "I'm block-scoped";
  console.log(blockVar); // Accessible here
}

console.log(blockVar); // Error: blockVar is not defined

Keywords | Reserved Words

Keywords are reserved words in JavaScript that cannot use to indicate variable labels or function names.

Variables

variables ==> stored values ==> it will stored to ram / It will create separate memory.so we need memory address for access the values.

Stores Anything :
JavaScript will store any value in the variable.

Declaring Variable :

 * Var
 * let
 * const    

we can declare variable using above keywords:

Initialize Variable :

Using assignment operator to assign the value to the variables.

var text = "hello";

JavaScript is a versatile programming language primarily used to create dynamic and interactive features on websites.
JavaScript is a scripting language that allows you to implement complex features on web pages.
Browsers have Interpreters. It will converts JAVASCRIPT code to machine code.
Browsers have its own interpreters like

• Chrome – V8-engine
• Edge – Chakra

JavaScript- Identifiers :

var message; –> Variable (Identifier)
message = ‘Javascript’;

func sayHello() {
console.log(‘Hello’)
}

//sayHello Is the identifier for this function.

//variables , objects,functions,arrays ,classes names are identifiers in js.

SCOPE :
In JavaScript, scope refers to the context in which variables and functions are accessible. It determines the visibility and lifetime of these variables and functions within your code. There are three main types of scope in JavaScript.

Global Scope:.

• Variables declared outside any function or block have global scope.
• These variables are accessible from anywhere in the code

example :

let globalVar = "I'm global";

function test() {
  console.log(globalVar); // Accessible here
}

test();
console.log(globalVar); // Accessible here too

Function Scope

• Variables declared within a function are local to that function.
• They cannot be accessed from outside the function.

example :

function test() {
  let localVar = "I'm local";
  console.log(localVar); // Accessible here
}

test();
console.log(localVar); // Error: localVar is not defined

Block Scope:

• Introduced with ES6, variables declared with let or const within a block (e.g., inside {}) are only accessible within that block

example :

{
  let blockVar = "I'm block-scoped";
  console.log(blockVar); // Accessible here
}

console.log(blockVar); // Error: blockVar is not defined

Keywords | Reserved Words

Keywords are reserved words in JavaScript that cannot use to indicate variable labels or function names.

Variables

variables ==> stored values ==> it will stored to ram / It will create separate memory.so we need memory address for access the values.

Stores Anything :
JavaScript will store any value in the variable.

Declaring Variable :

 * Var
 * let
 * const    

we can declare variable using above keywords:

Initialize Variable :

Using assignment operator to assign the value to the variables.

var text = "hello";

Understanding Routes

React- Router is used for render the components depends on URL without reloading the browser page. It navigates a page to another page without page reloads. we can use router in react project, first we install the react-router-dom package from react.

Then, access the router using

import {BrowserRouter,Router,Routes} from 'react-router-dom';

after that we use link to diplay the browser using Link instead <a href=''> in react.

so,

import {BrowserRouter,Router,Routes,Link} from ‘react-router-dom’;

example for using Link and routes:

Using Links:

  '/' is the root page it display default home page

    <Link to='/'>Home</Link>
    <Link to='/about'>About</Link>
    <Link to='/contact'>Contact</Link>

}/> }> }/>

Using Routes:

<Browser Router>
<Router>
<Routes path='/' element={<Home/>}/>
<Routes path='/about' element={<About/>}>
<Routes path='/contact' element={<Contact/>}/>
</Router>
</Browser Router>

Understanding Routes

React- Router is used for render the components depends on URL without reloading the browser page. It navigates a page to another page without page reloads. we can use router in react project, first we install the react-router-dom package from react.

Then, access the router using

import {BrowserRouter,Router,Routes} from 'react-router-dom';

after that we use link to diplay the browser using Link instead <a href=''> in react.

so,

import {BrowserRouter,Router,Routes,Link} from ‘react-router-dom’;

example for using Link and routes:

Using Links:

  '/' is the root page it display default home page

    <Link to='/'>Home</Link>
    <Link to='/about'>About</Link>
    <Link to='/contact'>Contact</Link>

}/> }> }/>

Using Routes:

<Browser Router>
<Router>
<Routes path='/' element={<Home/>}/>
<Routes path='/about' element={<About/>}>
<Routes path='/contact' element={<Contact/>}/>
</Router>
</Browser Router>